I like Foursquare - it's fun. But I see problems. For one, I can't see how it'll break out of its niche crowd. One of Twitter's is that it's simple and universally accessible, on the web or on the go with any device. Most of the folks I know outside tech circles wouldn't bother with a game. This presents a chicken/egg problem as the less of my friends are on there, the less inclined I feel to keep using it.<p>I like the direction they're taking it with getting local businesses involved. There's value in a frequent flyer points system for restaurants, etc. But simply 'checking in' without express ties to transactions probably won't cut it. Further, trying to extract fees from small restaurants and businesses is an expensive feat.<p>Hope they prove me wrong!