<p>You know you've seen it on your friend's Facebook profile or Twitter feed: a Foursquare check-in, proclaiming that they are now the mayor of the local burger joint. On Monday, Facebook praised Foursquare's use of open graph technology, which has allowed the program to grow by leaps and bounds. Foursquare Product Manager Noah Weiss noted that sign-ups rose by 50 percent after Facebook login was added to the application.</p><p>Foursquare, a service that allows users to gain rewards for checking into places, was looking for a way to make the app easier to use, especially on mobile. Previously, the three-click protocol that Foursquare used yielded a 60 percent conversion rate. After giving users the option to sign up with one-click using Facebook login, the conversion rate rose to 90 percent. By signing up with Facebook, Foursquare users can see which of their friends also love to check in.</p><p>Facebook, which put Foursquare in the developer blog spotlight, lauded the app's tagging ability users can tag Facebook friends when they check into places, even if that friend is not on Foursquare:</p><p>To integrate more closely with Facebook, Foursquare added the open graph mention tagging feature. Mention tagging is best when people are doing activities where they want to mention friends. When people mention a friend in Foursquare, the story on Facebook links the person's name to their timeline, and their friend will receive a notification. The story will also be added to the friend's timeline or, if enabled, to timeline review. No privacy changes are associated with the mention tagging feature.</p><p><a href="http://allfacebook.com/foursquare-developers-blog-spotlight_b106444">Keep reading...</a></p>