All Things D is reporting that Foursquare and Groupon may soon team up. It would give Foursquare a nice monetary stream since it would presumably get a cut of the deals people discovered while checking in somewhere. It would give Groupon a more specific set of customers who would be more likely to get in on a particular deal. That, in turn, would mean that the participating merchants could get a higher return of investment on the deals being offered. But really, this would be all about taking on Facebook together. Facebook offers both location and deals now and this is these companies teaming up to take it on.