I checked out the flash intro and logged into the live demo. It looks real great, especialy for a first release but going around in the client is extreamly slow (5-10 seconds before action hapens after clicks). My computer is a little older but the CPU didn't seem to be going up too much. It actually appeared to lock up a few times when I clicked more than once and it was still "processing". Clicking the back button in the browser re-inited the session and then it was ok again.

A couple other nasties:

- Is there any keyboard navigation at all?

- Resizing/moving calender items via drag seems like start time ends up 3 hours later than were it was dragged to. Also, time overlapping events don't go side by side but literaly overlap

- Idealy conversation view would be more a threaded view with expand and collapse [+] or [-] icon.