Second the bit about private calendars. To me this is about tracking my own productivity across all kinds of contexts (work, play, gym, diet); I can't even fathom a reason why I'd want to make data that span those contexts available to anybody / everybody.

The other bit of feedback - I have to wait a whole day until the app starts showing value. How can you make it add value immediately? What about sending me an email and asking me what I did yesterday? Or letting me enter it right on the site, since otherwise I gotta go fire up my email client?