The truth is that I only built this app for fun (first version was made to return the closest bar to each tweets from a specific friend) and curiosity (Node+Twitter+FourSquare) and when it began to get "bigger", someone suggested me to use a "real" design, with a logo, a presence, etc...
I'm no designer but using Illustrator to get something quickly was a nice break from emacs. The arrow was completely inspired by the FedEx logo (though by bad memory, it ended up being a bit different) and the colors were only ran through a "can I look at it more than five minutes without my eyes burning" test. But if you want to submit a better logo, I'll gladly take it =)
