Location-based services have been a popular topic this week, as Twitter enabled geo-location features and Facebook announced the launch of a new location-based feature in April. Another location-based social network, Foursquare, marked their one year anniversary of their launch yesterday. While the primary use of the service is to ‘check-in’ with mobile devices at local businesses like bars, restaurants, stores or nearly any location – however, a visit to the website is needed for the initial sign-up for Foursquare. As the service has grown, the visits to Foursquare.com have increased since the official launch at the SXSW conference in Austin, TX last year and the volume of visits have increased 5x for the week ending March 6, 2010 as compared to the week ending September 19, 2009. Partnerships with major brands such as Bravo, Zagat, The New York Times and Lucky magazine have also helped drive traffic to the website, and thus new users.

The main source of traffic to Foursquare.com is Facebook, which accounted for 33% of the upstream visits last week. Google and Twitter followed with 22% and 8%, respectively, with these top 3 websites accounting for nearly 2/3 of all traffic. Users are able to link both Facebook and Twitter to include check-ins in updates and tweets.

Searches for a portfolio of Foursquare-related terms have also grown over the past 24 weeks, spiking the week of February 20, 2010 and have remained fairly consistent over the past 3 weeks.

Yesterday, Foursquare announced breaking their record for the most check-ins in one day, exceeding 275,000 and we can expect that trend to continue with the start of the SXSW conference today.