Competing with Facebook: How Twitter gets it right and FourSquare gets it wrong (via Dare Obasanjo aka Carnage4Life)

Good description of differences between Facebook, Twitter and Foursquare here: 

This is where the positioning and focus of Twitter as a news service as opposed to a social network puts them in a good place in comparison to Facebook. Twitter is where I go to get entertainment and news about the topics I’m interested in from subject matter experts. These subject matter experts (in many cases bloggers, minor & major celebrities) are not people I know nor  have I met. This is distinct from my Facebook social graph but has some overlap depending on how much of a subject matter expert I am myself. On the other hand, FourSquare is a place where I go to share my location with people I know or have met. This set of people is almost always a subset of the people in my Facebook social graph. The only value additions you get from FourSquare are the game mechanics and deals (not anymore). FourSquare has unfortunately reached the point where the only practical difference between using it versus Facebook Places is that I get to be mayor of my local Gymboree and collect two dozen video game style achievements. Personally I’ve already grown bored with the game mechanics and suspect that targeting the console gaming demographic guarantees it will be a niche service at best.