Despite past speculation, Foursquare has remained a stalwart in the social "check-in" industry. Facebook, however, has decided to cut its losses and shut down Facebook Places. While geographical check-ins will not disappear from Facebook entirely, they will be combined with other features--such as tagging a photo with a location. On smartphones, stand alone check-ins from others will no longer show up in your news feed.
Foursquare will still be a dominant provider of social check-in and meetup services. With partnerships with American Express, Groupon, and Living Social, among others, Foursquare is solidifying itself as a force to be reckoned with.
Of course, let's not forget Google has a hand in the local check-ins as well. Google+ has a check in feature that should correlate directly to local search results and help Google Places in search.