More on Location Services Growth

4% penetration of the total US online market might not sound like much, but that's still a really big number. 4% is the figure for usage of location-based services like Foursquare and Gowalla, according to the latest Pew survey. To put it in perspective, a year after its launch, Twitter's penetration was 6%.

Another factor in the growth of these services is that existing social media sites have quickly added geo-location services into their existing offerings. Yelp added a check-in features a few months ago and Facebook did the same recently. It's important to note that the Pew study just includes the free-standing services like Foursquare and Gowalla; Facebook Places was not a part of this study.