yelp. I think this has the best chance of being useful to local areas. The problem with most of the ones mentioned are they are already worldwide and don't benefit from some sort of local culture. This is not always the case but generally. Local and something that is societally different from American culture that can't be captured just by internationalizing. Example: Mixi in Japan does well as a social network because of cultural differences. China is a huge market that tend to only like Chinese services.