The product is not unlike the popular Foursquare location-based service, and lets you “check-in” at a place and send a notification to your friends who are nearby.

这个产品和现在流行的Foursquare地理定位服务不同，它可以让你在某个地点“签到”，然后会给你这个位置附近的好友发送消息。

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But the company is mainly built on the location-based check-in service.

FORBES: Why Facebook And Booyah Could Burst Foursquare's Location Bubble

Time magazine, for example, has formed a partnership with Foursquare, a location-based mobile check-in service, for the conventions, in which Time has provided content that users can unlock when they get to certain locations in Tampa and Charlotte.

WSJ: Online Media Will Star at the Conventions

Unlike some Web-based phenoms, the location check-in service Foursquare has an obvious potential business model: local ads based on your geographic location, perhaps coupled with inferred interests from your previous check-ins.

FORBES: Foursquare's Dennis Crowley: It's Still About Growth, Not Ad Money (Yet)