Very true. Providing incentive for people to contribute here is key. We're still brainstorming ideas and are looking for suggestions.

The reason we decided against scraping these other sites is that few people actually check-in. In a full bar, it'd be optimistic for >5 people to check in. This makes ratios very inaccurate. There actually is a site out there based on Foursquare check-ins and they suffer from this problem.