Whrrl
Whrrl is a social location-based gaming component developed with a purpose. It is meant to get you out there and try new things. It was launched as a discovery site that allows both mobile and web users to find, explore, meet up at, and share points-of-interest in their cities. Unlike Gowalla and Foursquare, there is more to Whrrl than check-ins and coupons. It allows you to annotate your visit with images and notes to create virtual scrapbooks.