The entire idea behind this blog post has been summed up in the title, so all I need to do now is to explain why I think email should have expiration dates, and how that would make personal information management better.
Email, as we all know, started off as a way of sending short messages to colleagues within a department. It has since evolved into a monster of a tool that does everything it was never designed to do. The paradox is that it is exactly the kinds of messages that email was designed to handle that cause me the most trouble these days.
These are the kinds of messages I'm talking about: important but time-sensitive. Then there are others which are not really important, but simply one-time notifications that I can take action on and then forget ("bill is due in 2 days", "X added you as a friend", "your order was received", "your package has shipped", "free donuts in break room", "we are not meeting today", etc.)
Why do they linger on in my mailbox for years? They become indistinguishable from the really important email that I need to save for years, such as some very interesting and intelligent discussions I have had with others. Note that I'm not including spam in this discussion, because in my opinion, there are adequate spam-filtering tools circa 2008 that perform well enough for most users for the most part with an acceptable false positive rate. Not perfect, but acceptable.
Email is no longer ephemeral -- people hold on to their email for years. This is what results in the Keeping Problem in Personal Information Management: there is so much of information coming at us that we don't want to spend the time to decide what to keep and what to trash, so we end up keeping all of it. We hope we never have to do spring cleaning, and instead rely on search to find what we want.
Many people file and tag their email, but the question is, is the cost of doing so (time as well as attention) worth the payoff at the end? Consider the two alternatives: spending 10 minutes each day filing your email, versus spending an hour a month looking for that one email. Pretty soon, the second alternative starts looking better while swimming in a sea of email with no signs of abating.
The bigger the haystack grows, the harder it is to find the needle. The solution is to reduce the size of the haystack. Automatically. Most other solutions empower the user to filter, sort, file, tag and do other sorts of things to their email that do not scale very well. That's where Email Expiration Dates come into play. For it to work, they need to be (1) defined and (2) honored.
Email expiration tags can be defined in several ways by several entities that handle the email message at some point of time in transit.
RFC 822 allows custom tags (Sec. 4.7.5). These are commonly referred to as X- headers, since the specification requires that all such tags be prefixed with "X-". Many applications built on email make use of such tags: mailing lists use the X-List-* headers to specify the list name, subscribe URL and unsubscribe URL in a mail message. Spam filtering software such as SpamAssassin assigns a score to each email, saved as an X- header. Mail clients are free to interpret these tags as they see fit.
An expired email will not be automatically deleted if the user does not want it to be. This is important for archival purposes and to satisfy the stringent reporting requirements of the Sarbanes-Oxley Act. But now the user can make a one-button choice about whether or not expired emails be deleted, archived, moved away or kept around.
Bulk mail such as Facebook notifications could have expiration dates set to "one week after receipt". Bill reminders could set the expiration date to be "2 days past deadline" (and then send another notification if payment is not received by then.) Donut announcements could expire at the end of the day. Talk announcements could expire at the end of the talk.
Returning from a vacation is no longer refreshing, as we are thinking about the sheer volume of email we need to process once we get home. If I was on vacation when the donuts were on the table, I should not be bothered about it when I return. Go away! If it's an invitation to a talk that happened while I was away, I don't need to hear about it now.
Defining a standard is no use if it isn't used. The best way for such a solution to be adopted is for a major email provider implement it themselves, perhaps in a limited beta? On the interface side, this requires two additions: one for sending, one for processing received messages. The widget at the sender's end is simply a calendar picker, or a drop-down with relative dates ("tomorrow", "next week", etc.) At the receiving end, it's a three-way radio button that lets users "Delete", "Archive" or "Leave alone" expired messages.
Till then, it's back to manual spring cleaning. Oh well.
Acknowledgments: I have had several stimulating discussions with my advisor, Manuel Pérez-Quiñones, and my colleague, Pardha Pyla, about our respective email filing strategies, (that mostly began as venting sessions). This idea no doubt borrows from my analysis and conclusions based on some of those conversations.