Right, I completely forgot about this! I even bought Unibox on the Mac App Store when it came out! But while I loved the people centric concept, I just didn't like the design...

EDIT: I just downloaded it again, and here's why I don't like Unibox: it has a very low density design. It looks like a fancy website, rather than a productivity app. Lots of space is wasted on frames and borders. UI elements appear and disappear as you move the mouse. It's definitely a modern app, but I seem to prefer more traditional apps...