Barack Obama has signed up for a Foursquare account. From the White House Blog:

The White House is now on Foursquare, a location-based social networking website, which is the latest way for you to engage with the administration. There are over 10 million people already “checking in” around the world, and now you’ll be able to discover “tips” from the White House featuring the places President Obama has visited, what he did there, plus historical information and more.

The location-based network makes sense and the President’s account may well make for interesting reading when the 2012 campaign goes into full swing. Source: Mashable