It's obvious that Facebook sees serious potential in mobile check-in service Foursquare: it tried to buy it for $125 million.
That didn't work. So Facebook started to get into the location game, too. It launched Facebook Places, its own geolocation service. And today, Facebook went ahead and launched a big new suite of mobile features that includes, notably, enhancements to Facebook Places that let businesses easily automate "deals" for when users check in. On the surface, given Facebook's scale, this looks like it could spell difficult times ahead for Foursquare. See also
Facebook Deals A New Threat To Google Places Search (LA News Monitor)