Mashable has a report of a patent that just issued (6-1/2 years after filing) — apparently Google now has a lock on location-based advertising. It's not clear that the search company intends to assert the patent against any other companies (such as emerging rival Apple), but it's useful as leverage. Here is the patent.
Update: 03/02 14:34 GMT by S: Reader butlerm noted that the incorrect patent was linked. It now points to the correct URL.