First Impression: For some reason, unless I can see an example of exactly what this looks like / a demo I can't see myself signing up.
Signing up was fairly quick. However making my first post was a little troublesome: Hitting the "enter" button when didn't seem to post anything. The overall feel here feels less like a diary and more like a self-contained twitter feed. I think it's the atmosphere of the application that is throwing me off the most.
Congrats on shipping a product though! I'll continue to try it out.