For the past few months I've been working on web apps. The first was a mobile site based on jQuery Mobile. While it was "cool", it quickly dawned on me that it wouldn't get any significant usership. For one, it was like a clone of 4square and Scvngr - and who really uses that? I'd peer into the lists of checkins, and it wasn't looking too encouraging. People use it when they're bored and alone, and my scenario didn't involve either of those situations.