Almost from the start of the very first Location Based Networks in 2008, they stimulated retailers to launch promo's for those customers who "checked in" at their local stores, pubs and restaurants.
During the first year I noticed lots of successful actions and promo's starting up in the USA and UK, some even nationwide (e.g. promo's of Starbucks, Domino's Pizza, ...)
Pioneer Foursquare has a great business page, listing the latest promo actions nearby.
It seems that after the summer of 2010 Belgium and Holland also noticed the positive aspects of these promo's and finally jumped on the wagon. Especially near larger cities, it happens more and more that when you check in somewhere, you'll be attended to "Special Promo" actions nearby.
Only yesterday I was attended to a promo by a local bookstore in Maastricht (NL) where they hand out free bestselling books to customers who have checked in to their store at least 10 times.
If you are active in retail or horeca ... take action now and get more customers.
Location based networks are very clever marketing tools and free to use !!!