"Foursquare who?" asks Google, as they roll out 60 check-in offers in Austin, Texas, to coincide with the SXSW nerdfest. All users have to do is check into the business, say a cafe, and see if they're offering any special deals.
Over time, you will be awarded special status, as either a "Regular", "VIP" or "Guru", with businesses able to offer these different levels various "unlockable" offers. Google Latitude = officially now a real-life video game. [Google Blog]