An innovative feature for a PIM: stamping.

Interesting feaure:

Yin explained the latest thinking on items. Most PIM programs required users to decide up front, when they created a new item, what it was: Were you creating a new email? A calendar event? A to-do task? Chandler would instead let you sit down, start typing a note, and decide later what kind of item it was. Like the human body's undifferentiated stem cells, notes would begin life with the potential to grow in different directions. This design aimed to liberate the basic act of entering information into the program from the imprisoning silos. It also made room for Yin's proposed solution to the item mutability problem: The mechanism users would employ to specify the "kind-ness" of an item would be called stamping.

Say you had typed a note —a couple of sentences about a meeting— and then wanted to put the meeting on the calendar. You would stamp the note as an event. Chandler's detail view would add fields that let you specify a date and a time; your generic note was now an event. Later, if you wanted to invite a colleague to the meeting, you could take the same note and stamp it as an email. A "to" field and a subject line would appear in the detail view. You would fill it out and click on a "send" button.

(Rosenberg: pp. 189-190)

I don't think any other existing PIM software allows you to do that. Apparently, many of these innovative features in Chandler are actually carried from Lotus Agenda, an old piece of software that Kapor wrote back in the Lotus days. It's a pity that today's PIM software is, for the most part, quite run-of-the-mill. When it comes to doing simple things (i.e., dealing with email or taking care of our appointments on a digital calendar) they are too complex and prone to corrupt our (valuable) data. As a matter of fact, it wouldn't be the first time I try to use one of these fancy applications and always end up reverting to good old time-tested mutt. No, mutt is not cool and fancy with all its bells and whistles, but it is extremely flexible, it lets me configure it precisely the way I want it and, above all, I can trust it with my email. I won't corrupt the data as soon as the email folders are too large, forcing me to deal with an emergency crisis at the worst possible moment. So, if I am going to use one of these newflangled applications, it'd better be something different, creative, innovative. It'd better be something that seemlessly links my email to my calendar, my tasks and my contacts. Otherwise, why even bother with a new app?