You may or may not have heard of Foursquare.

Loosely put, it is a game that gives you points and status when you “check-in” to a specific location.

What’s so interesting about the growth it has been experiencing, is that in Foursquare, you are starting to see the seeds of the long-promised “geo-location services.” Beyond that, the opportunity for physical locations to connect with their fans…when they are there.

For example, I was at the Zoo a few weeks ago and checked-in.

What’s interesting here is that the Zoo now has the capability to know that I’m there and engage with me.

They can identify their Raving Fans who are walking around the zoo, give them opportunities to participate in unique activities, allow them to promote certain activities, bring them together to cultivate them, and much more.

Mashable had a great post on this a few weeks ago in terms of the potential as it relates to Tasti D-lite and their building of customer loyalty programs into Foursquare as a marketing platform.

Robert Scoble also had a good post on what makes the site so addictive (I’m not there yet, but certainly could be).

Kind of like the “Google Street View Marketing,” we are seeing a further blurring of the lines between online and offline into a seamlessly integrated customer-business experience.

I’ll admit that I don’t fully have my head around it yet, so there’s more to come on this, I’m sure.