I think this is an interesting concept, if executed well. It would be nice to see a sample of one of the summary e-mails that gets sent out the next day (without that, a lot is left to the imagination).
What I'd like to imagine is a system where you reply to the "wrap-up request" e-mail with one event per line, and a dead simple format for processing (server-side) what those events mean. For example, a line starting with a '+' is an item being worked on, one starting with a '-' is a completed item, a '?' is an issue or question for the team, and a '#' is a comment.
Then, on the server side, you categorize all of these events and automatically plug them into a calendar with times and a link to an auto-generated profile for the event poster (the one who replied to the e-mail) showing their entire event history.
The summary e-mail that gets sent out the following day, then, would be broken up into the four aforementioned categories (Questions/Issues, Comments, Completions, and New Work).
Anything in that general area would make for a swell product, I believe :)
Also, a couple minor points: You should increase the lightness of the grey foreground elements on your website (they'll be difficult for some people to see as is, due to low contrast). Also, if you lose the drop shadows on the foreground elements that have them (e.g., the cursor), you'll have a cleaner looking design.
Hope this helps!