When Facebook launched its new Places feature, writers all over the Web were lamenting that it could be the death sites of sites, like Foursquare. These calls were clearly premature.

Foursquare hit the 3 million mark over the weekend.  This on top of the record number of new registrants the day Facebook's Places was announced.

All this progress is raising the question: What effect does this have on the world of check-in based social media sites?

Granted, it is not much compared to the 500 million users that Facebook claims on its site. It is however a significant increase for Foursquare's user population. It represents a sharp uptick in user registration since August 2, when the site had just over two and a half million visitors, and more than quadruples the 725,000 users Foursquare had in March of this year. It may turn out that Facebook has simply raised awareness of this technology.

As for Foursquare CEO, Dennis Crowley, he isn't to worried. He said "Everyone keeps saying, “Oh my God, you guys must be so stressed with Facebook getting into this.' Not really. We spend a lot of our time telling people why location is important and why people want to check in. Facebook now gets to do that for us. We can focus on the stuff we want to do," in a recent interview given to The LA Times.

As a matter of fact, they may even be doing it subconsciously, since its logo looks suspiciously like a square with a four in it.

In that same interview, Crowley also cited a similar example of another Facebook-was-going-to-kill-the- competition hype, "Look what happened when Facebook got into Twitter’s space. People said Twitter was gone. But it just made Twitter stronger and more focused. Our services are totally different. They do different things, serve different needs and different people."

Foursquare is relying on its appeal to a different user group, the integration of gaming into their location based system and an impending redesign to keep them growing in the future. The redesign will let users create and share to do lists with other users. This could be used for digital scavenger hunts, or for real time errand collaboration.

Foursquare currently has a Facebook page, with 105,310 fans.