Friday, July 07, 2006

How Researchers are Reinventing the Mail Client

For the last 10 years, the three-pane has been the standard view of looking at email. A pane for folders, a pane for folder contents, and one showing the selected email. Even though mail clients are highly configurable, this has been the standard view of many users. It isn't likely to change soon: The beta of Microsoft Outlook 2007 – pictured below – sticks with conventions.

Email today has many annoyances. Even though we now seem to have a grip on the spam problem, many users are suffering from email overload: There are just too many emails flooding the inbox. Many are drowning in heaps of emails that aren't even important – it's just a colleague at work Cc-ing everyone evenly remotely connected to his project.

There are plenty of ideas on how to improve the current state of mail clients, and I'll present some of them here. None of this is my work: I'll give references to publications of others. There are literally hundreds of papers on this subject, so I've chosen to present my selection of personal favorites.

Here are the three ideas I'll present:I'll present one example from each category.

Task-Driven E-Mail Organization

People's lives today are organized in their mail client. It's not just communication that takes place here: Meetings are organized, lists of todos and deadlines are exchanged, documents are sent around.

In effect, what you're keeping track of in your email client are tasks. Most emails you get are part of some project, belong to an event you're attending or organizing, or are part of a greater plan, e.g. keeping in touch with a girl.

That's the idea behind TaskMaster [2], a tool developed at PARC in 2003. All your emails, drafts, attachments, and bookmarks are mapped to "thrasks". Emails in the same thread are grouped automatically, but the user still has to assign other mails, links, and deadlines manually.

Thrasks can have associated actions, such as "call this person", and "review this". You can also add deadlines to each task: they are shown as green and red bars as they approach. Documents can be previewed right inside TaskMaster's UI, as seen with the Word document on the bottom.

I think the great advantage of this approach is that items that belong together are displayed together. Instead of using email folders to hold related messages, the central element is the task, with all the associated deadlines, todo items, and documents.

Here's a quip from the paper's usability interviews:

"It's just nice to be able to have the control over mixing [...] related things together, even though they might not be [...] the identical kind of thing."

What if we went a step further and looked at workflow patterns? For example, at a company where you interview candidates in a formal hiring process, you get automatically generated messages reminding you of the interview, requesting feedback after the interview, and a notification of the final decision. In the future, we might be able to automatically identify the structure of such processes [4] and classify email into these activities [5] – both of which goes beyond Taskmaster's model, which requires some manual effort.

Creating Smart Organization Structures

Almost everyone I know keeps incoming email entirely in the Inbox. Newly arriving messages join the 500 messages already marked as unread and are displayed at the top of the pile. Is there a better way to organize this view? Can we sensibly restructure incoming mail?

Bifrost [6], a plug-in originally conceived at Lotus Research, that takes this approach. The idea here is that the people are the main indicators of whether an email is important. After installing Bifrost, you're asked to sort your contacts into five groups: Your own email addresses, "VIP Platinum" (extremely important people, e.g. your manager), "VIP Gold" (important people: friends and family), as well as small and large distribution mailing lists.

Bifrost then reorganizes your inbox and displays your email in a number of predefined categories:
  • Timely: Emails that contain today's or tomorrow's date in the subject line. They'll likely be important today, but not next week.
  • VIP Platinum: emails from your manager.
  • VIP Gold: emails from friends and family.
  • Personal: replies to emails you've sent out, emails sent directly and only to you, and any unclassified emails you receive.
  • Small distribution: Intended for group messages.
  • Large distribution: Large-distribution mailing lists.
Below is a mock up of what this looks like in practice. (I had to draw this up myself as the screenshots in the paper were too small).

This structure is helpful in identifying important messages and weeding out the less interesting ones. A quote from their user interviews:

"If I am running through an inbox, I might be tempted to read a title and get sucked in because it is interesting. Whereas if it is in a pile of listserv stuff, I just ignore it altogether. That was a nice thing when I was busy, to not get distracted by unimportant mail."

It's interesting to note that except for differentiating small and large distribution messages, this approach can already be replicated in today's email clients. You can simply create search folders or message filtering rules which simulate the Bifrost behavior. However, this would put emails into folders and wouldn't offer the one-page overview that Bifrost has.

Cool New Features

ReMail [7] was a project at IBM Research that ran from 2001 through 2004. It was basically a reimplementation of an email client from the ground up and had several cool new features. I'll describe two of my favorites below.

Thread Arcs visualize relationships between email messages. Instead of wasting lots of space with a tree view that Thunderbird has, it displays the thread structure in a little image. This feature helps you see where you are in a long conversation. For example, in the picture below, emails B, C, D, E, F, and H are all direct replies to A, while email G is a reply to E.

The advantage of thread arcs is that you can see the position of the email you're viewing in the larger conversation, without having to switch to a tree view: your main inbox pane remains sorted by arrival time.

Contact Maps offer a different view of the address book: Senders from which you have received email are grouped by domain. Each person's name is shown with a different background color, depending on the time of the last email exchange. This offers a better view of your contacts than the traditional non-grouped lists where your least important contact looks just like your most important one.

Many of ReMail's other ideas can be found in today's popular clients: Instant messaging is now integrated with Gmail, which also groups emails by thread. The collection mechanism in ReMail is semantically equivalent to Gmail's labels. Outlook integrates emails and calendaring and has list separators ('today', 'yesterday', 'last month'), just like the ReMail prototype.


It seems like the ideal email organization tool would be like your personal, smart secretary: It knows what's important or interesting, and deals with stuff you don't want to be bothered with. That would be perfect.

Today, we seem to be at a point where it seems like we might be able to solve the spam problem. But the problem of figuring out which of the non-spam emails is important, and what it relates to, still exists.

One solution – the one I presented here – is to add nifty features to the mail client. But would all these features really be understood and used? Users today seem to be using a very basic set of mail client functionality. Anything we add should not only solve a painful problem, but also be easy to use. I'm not even sure this applies to the applications I've shown here: You don't know until you've tried.

What do you think? Are these good ideas? Would normal people who are drowning in email use these features? What features can't you live without? Post a comment and let me know.


Thanks to Keno Albrecht, Bálint Miklós , Markus Egli, and Fabian Siegel for reviewing drafts of this.



A more thorough and academic overview of the subject:
[1] Steve Whittaker, Victoria Bellotti, Jacek Gwizdka: Email in personal information management, Communications of the ACM, 2006

Examples of task- and activity-based systems:
[2] Victoria Bellotti, Nicolas Ducheneaut, Mark Howard, Ian Smith: Taking email to task., CHI, 2003
[3] Michael J. Muller, Werner Geyer, Beth Brownholtz, Eric Wilcox, David R. Millen: One-hundred days in an activity-centric collaboration environment based on shared objects, CHI, 2004
[4] Nicholas Kushmerick, Tessa Lau: Automated email activity management: an unsupervised learning approach, IUI 2005
[5] Mark Dredze, Tessa Lau, Nicholas Kushmerick: Automatically classifying emails into activities, IUI 2006

[6] Olle Bälter, L Sidner: Bifrost inbox organizer: giving users control over the inbox, NordiCHI, 2002

[7] ReMail: Reinventing Email Website, Collaborative User Experience, IBM Research, 2003


Anonymous said...

Nicely done! I really like your ideas and would hope that somebody who knows how will devise a mail client with the features you suggest. Thank you, Vic Kryston

danfrg said...

i like the ContactMaps you showed. it would be interesting to see that for my set of contacts. same for the task-based e-mail client: neat to see deadlines as they approach.

Anonymous said...

Great article, thank you. Let's hope these ideas will be implemented in mainstream email systems soon.

Kaitlin Duck Sherwood said...

You've done a great job of summarizing the academic research!

I think the perfect email client should push those good ideas a bit farther. Email clients should group messages in the inbox (like BiFrost) based on what group the person belongs to -- old classmates, current colleagues, family, friends, etc. Yes, there will be some overlap sometimes, but the overlap is usually small, and the email client could show those people in two different groups.

This would require that users tag each contact with the group(s) that they belong to. For extra credit, the perfect email client could make a first-cut guess at who was in what group, based on your past correspondence patterns.

Finally, there are some really simple capabilities that would help a lot. For example, it would be nice if you could set it up to change the color based on how you were addressed: red for "to me and only me", blue for "to me and other people", down to grey for "I'm bcc'd and have never corresponded with the sender or any of the people on the TO or CC list."

While it is a little out of date, I wrote a list of the things I think belong in The Perfect Email Client.

Pierre said...

Thank you for your thoughtful comments. Email is indeed a mess. We are just beginning to recognize how it disrupts our work patterns.

Donald Knuth, the pre-eminent computer scientist, has said that he is "a happy man ever since he stopped doing email in January, 1990".

Nevertheless, the rest of us are stuck with it.

I am pleased to say I never have more than 8 things (usually 3) in my In Box at any one time. I use Eudora, and group my email by person that sent it, within type of organization: Partners, Customers, Personal, Vendors, and fellow employees.

I sub-divide vendors by type of product or service.

It's not perfect, but it gives me some control.

I like to use the colored labels that can be assigned to email: "Printed", "Replied to", etc.

I also use Spam Arrest to block spam.

Gabor said...

Kaitlin: Thanks for the link, I read your article and it was quite interesting.

Points 2 and 3 what some of the papers had observed: People use emails for keeping track of todos, not just communication. We'll need to add some good task support to mail clients eventually.

The collaborative URL filtering service you mention in 14 exists! The Earlgrey Filter of Spamato does just that. :-)

Pierre: Knuth recently gave a talk here in Zurich and if I remember correctly, he said that his secretary sometimes prints out copies of emails for him. Seems like you can't avoid email altogether.

Ken Wilbur said...

I'm really not sold on any of these ideas.

The first one will generate huge amounts of unwanted, automatically generated emails that will drive corporate workers insane.

The second one- task driven email- is interesting but poorly conceived. Here is my version: add a 'task' pane to the email browser, and a 'task' toolbar to the email reader. When I get an email that I will use to remind myself of a future task, I only need click two buttons on the toolbar: date, time, and 'enter'. Then the email shows in the task toolbar and I get reminders as the deadline approaches.

Organization structures- maybe. Can you imagine what would happen when your wife/mother/son found out they were not on the "VIP Platinum" level? Also, the # of recipients thing is bogus. Lots of listservs just BCC all of their recipients.

Graphical conversation representation- imagery is always welcome, but I don't see this as a radical improvement. Yawn.

Contact maps. Maybe. But how many people really use this feature? Most people I know just hit 'reply'.

How about a new idea? I would like to see an email program that analyzes how much time I spend perusing each email, by source. For example, how many hours did I spend on personal email? Reading mass email? Who do I reply to most often?

You state that people are overwhelmed by how much email they get. But none of these technologies deals with that issue. What people need are tools to analyze how they spend their time with email, and how they can make their time with email more efficient.

stanross said...

IMHO I think the answer is not in re-defining how email is organized or by designing a better email client, but in redefining how work is done, how activities really take place (and modifying that) and re-assessing how communication takes place (whether online or off-line). I just think the answer is not in email.

Keno Albrecht said...

Ken: Seems you are looking for something like Xobni Analytics (not released yet). From their product description: "Have you ever wondered how much time you spend each day using email?"

Phil said...


I wrote an IMAP server called
Decimail as a platform for investigating this sort of thing. It uses a PostgreSQL database to store messages, and defines mailboxes using queries on the database. Many of the things that you suggest can be implemented in this framework if you write the right queries. On the other hand, Decimail Server talks to a client using regular IMAP, which constrains it. To make this sort of thing develop we need a way of enriching the client/server communication, so that new features can be added in the server that become accessible in all clients.

Thanks for the article.

David said...

I'm about as biased as you can get, but check out - trying to do something new with email...

Gabor said...

Ken: Thanks for the comment.

I, too, think that task-based solutions seem promising. The UI issue of how you enter todos and deadlines is open for discussion, of course, but the underlying idea stays the same.

Most wives will understand that they're "VIP Platinum" at home, but not at work :-)

The listserv stuff would work by looking at the sender and reply-to. It would catch the Bcc-All listservs as well.

As for your statistics idea, I hope Xobni will help. :-)

stanross: Not sure I understand what you mean. In your view, how should we communicate at work? IM and phones are options, but that would be annoying. Snail mail is slow. Person-to-person real-time communication does not scale well, especially when you're in different countries.

David: Taglocity looks neat. I'll give it a try (although my main mail client is actually Thunderbird).

Anonymous said...

Thread Arcs would quickly get unweildy if the thread got to be more than 15is emails long.

Too bad, since it seems like the best proposal in this article.

Dascamel said...

I think the biggest hurdle to using email, is people don't use their clients correctly. I am constantly telling my boss to send me tasks thru outlook rather than an email that I have to flag and track myself. How many of your current emails are actual tasks that could be tracked and documented in one place??? That is a better question you should be asking yourself.

Lampajoo said...

My Nifty Features:

-a mood flag for each email that displays what kind of mood(happy, mad, sad, etc) the writer of the email was in.

-an "understudy mode" where the program tracks the email you receive and what your responses are then when you go on vacation it will attempt to answer your emails as you would have.

-an "active understudy" which will send out periodic email "pings" to distant friends, old college buddies, etc

-your email answering clone should be able to know whether an email will hurt your feelings and may edit it or withold it to help you out, e.g. "I'm breaking up with you because you have a small penis" in an email from your girlfriend would get xlated into "It's not you, it's me."

Anonymous said...
SNARF was built around the notion that social network information that is already available to the computer system can be usefully reflected to the user: a message from a manager might be seen differently than a message from a stranger, for example. SNARF applies this idea to email triage: handling the flow of messages when time is short and mail is long.

Anonymous said...

If you're interested in visualizations to assist email, you should check out the brand new work of the University of Maryland and Microsoft Research:

The most recent paper, published in May, features 3 new visualizations ( )

Anonymous said...

good article. after years of hundreds of emails in my inbox basically shut down my productivity, i realized that email was best viewed as a task-driven tool. now, i immediately archive anything that's not actionable and have been <30 emails for 3 years.

"However, this would put emails into folders and wouldn't offer the one-page overview that Bifrost has"

I use Outlook rules to apply categories to emails and use a group-by-category view to get the most important ones at the top of my inbox.

Dickson said...

The ideas are really well articulated and excellent. I would use most of the features i have seen and currently trying to use the mail tags in mail for the mac which seems to embrace most of this concepts well.

Renald Loignon said...

I suggest you look up John Gilmore (Internet pioneer, maverick, etc...), and his concept of a smart Email client ("Grokmail").

Among the search results, there is one pointing to a client-side proxy implementation of the Grokmail comcept, under the name POPFile.

I had see POPFile mentioned before, but now that I see it's source of inspiration, I plan to check it out soon...

Brad Meador said...

Gabor - I'd love to hear your thoughts on the design behind my company's email prioritization engine for Outlook. I have posted a link to our design whitepaper here:

I look forward to hearing your feedback.

Brad Meador

Gabor said...

Hey guys, sorry I'm a bit behind on processing comments. Here are a few things:

Lampajoo: Great ideas, that would bring us closer to mail client = secretary.

The mood flag might even work if you have enough text and a good profile of vocabulary -> user mood.

I've been thinking of "active understudy"-like things as well. That should improve my terrible keeping-up-with-old-friends behavior.

Anonymous who posted the MSR / UMD links: Thanks, I didn't know that work before (although I've seen some stuff by one of the authors). Will read it.

Snarf / POPfile: Yes, I've read those papers (there is literally a huge pile on my desk), will post my thoughts later.

Oulook "Group by Category": ooops, I missed an Outlook feature. I was thinking too much about folders.

Brad: thanks for the link, I'll read it and get back to you.

Herbert M. Sommerer said...

I would love to have thrasks spanning over the whole of my yearly e-mail archive aka personal folders.
Whenever I sort in the current folder it should replicate in the archives, provided there is a copy of it (inlcuding restructuring folder names or thrask names & sub-elements)

It should be able to link thrask trees/webs from the 'archives' to the current 'Inbox' tree/web

And then whenever somebody renames the thrask-name or subject line or whatever, the mail-system should still recognise it for you it as the same thrask (through internal ID). Maybe there should be a voting system of how the t(hr)ask should be named.

Jo Vermeulen said...

This is also an interesting read:

Visualizing email content: portraying relationships from conversational histories, FB Viégas, S Golder, J Donath, CHI 2006.

Core.B said...

Did you ever take a look at Chandler?

Grey Consulting said...

Gabor, Excellent research. I couldn't agree more with your conclusions. In fact, your entry inspired me to blog on the topic

Donald said...

An actual product that is very good is NEO - Nelson E-Mail Organizer, which is an addon for Outlook that works without changing the underlying program. It doesn't have nifty threading but it gives views like 'today', 'yesterday' or views on people.

Deva Hazarika said...

I notice Brad already tossed in a mention of our company's product, but I wanted to make a couple of points that specifically address your final questions.

We've been focused on commercial implementations for MS Outlook of ideas like the ones you mention for the past few years. One of the primary challenges is finding the right balance between providing useful, automated functionality to the user while not overwhelming them with complexity and overhead.

One of the biggest changes in email over the past few years has been the amount of email that deals with actual workflow and action as opposed to just communicating information. To that end, we've found that the core of addressing the email overload problem largely consists of three simple points:

1) Identify how important email messages are (who sent it, who it's sent to, how involved you are in the thread, and many other factors play a part in this)

2) Take required actions on the email quickly (current email interfaces allow for single-click reply/delete/forward/etc - information actions, but single-click workflow actions like defer, create tasks, create appts, etc. are now just as important)

3) Organize emails, tasks, and other items together in a way that makes the information easy to retrieve (this means not only creating tags and folders for emails, but also linking related emails, task, appts, and other action items)

I believe the fundamental driving factor causing email overload to continue growing as a major problem is the fact that email clients are largely built around a metaphor that is about exchanging information, while email has largely morphed into a sort of lightweight project management and workflow system for many users.

ralfgugginger said...

this is a bit off topic, but may interesting for you: "the best outlook tip in the world"

Anonymous said...

Gabor - interesting research thanks for posting. I noticed that your screenshot of Outlook 2007 is missing the To-Do Bar and makes no mention of the new flagging system. It sounds like something Ken Wilbur might be interested in. For more see:

Gabor said...

Last Anonymous: Thanks for pointing that out!

Yes, I am aware of the functionality that Outlook offers. I saw that the Todo Bar in Outlook 2007, and liked the fact that the Todo list is automatically filled with incoming emails - very useful.

The "TaskMaster" point from the post talks about something slightly different, though: Several emails are semi-automatically grouped to the same task. The group of emails provides a context for the task you're working on. My beta of Outlook now offers a command to search for all messages in the same thread, but that's not quite the same. :-)

Ray said...

I think Anonymous's approach above of archiving his emails immediately is the best, and the only approach that even approaches the problem properly.

We have too many emails and the point is to get that down.

I also now brutally archive/ditch emails asap. My inbox is typically less than 20 mails or so. Anything really important tends to come back to me anyway, either by a "louder" email, a phone call, MSN, etc.

"Todo" emails get converted into a calendar item as soon as possible.

This way, I no longer have outstanding emails that require attention, and they are at most archived only for reference.

Another trick is to have anything you are not certain about put into a "ToRead" folder, and then go through that folder only at specific times of the day or week.

That way your inbox stays clear and your time wasted on emails goes way down.

Gabor said...

Dear Anonymous from July 10, 2006 1:38 AM: I promised you to give my opinion on SNARF, so here it is (better late than never).

The basic idea behind SNARF is to collect email communication data for each of your contacts. For example, you collect information on:
- how many emails have I sent to Bob?
- how many emails have I received from Bob?
- how many times did I reply to his emails?

You can then sort your contacts by any of these attributes (see Table 1 of the paper for a complete list). The goal is that this helps you identify important people and emails, and I think it helps achieving that goal. It's actually a neat idea.

Unfortunately, I didn't manage to install the demo with my Beta of MS Outook 2007, so I coulnd't try for myself.

The only thing I don't find convincing is that people from which you receive lots of emails are especially important. For example, I have a friend with whom I exchange about 1-2 emails a day ("Check out this site I found on reddit!"), but as you can guess, most of them aren't that important. With anything but the "recent importance" indicator from Section 5.2, he would still get a huge boost in Snarf.

Also, I don't exchange a lot of email with my professor, but you could argue that he is fairly important. :-)

Kevin Cannon said...

Great post!

The Themail project is also interesting, though it takes a different focus with the aim of discovering themes within mails over time. It's an innovative approach that could be worked into an email client:

I'm not entirely sure email software can solve the email problem. UI designers are attuned to believing that problems can always be solved by improving the UI, but sometimes you've got to just rely on the user to fix the problem.

Gmail did this by really forcing the idea of archiving emails and providing a good search tool. Although I don't use gmail I'd already begun using a similar approach. The only messages in my Inbox are ones that I need to do something with. E.g. - reply to, send on or print out. Everything else gets put in and archive folder, or else sorted into a specific folder based on group. E.g. - business, online shopping etc... I use this approach quite successfully for my email now and never let things slip. It works for personal and work email and it makes me think that in many respects a successful email client may force a user into a specific usage pattern, rather than trying to guess which way they send and receive email.

Anonymous said...

ReMail looks the business. I could certainly work with that as my main client. The workflow is so simple it hurts and yet maintains full productivity...

Great article BTW!

Felipe Costa said...

It is a great article.

I would like to thanks Gabor and everybody who contributed with links by commenting...

It will be useful to my Master Thesis that I'm starting right now.

Felipe Avila da Costa

Felipe Costa said...

By the way, what you think about IM2000 approach to solve SPAM issue?

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Unknown said...

I am writing a Master Thesis on Emails. Your article is very good. We are now in 2012. Il look like the Email client didn't change much since the time you wrote your article. What came additionaly to Email is Instant Messaging. I think this is a bad evolution.

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