The document summarizes a mobile usability study conducted for the Sprite Yard, a proposed mobile social network for teens. Key findings from the study include that teens were very savvy with mobile devices and had high expectations for mobile applications. The study also revealed technical, device, and situational challenges that are more difficult to control in a mobile context compared to web usability tests. It was found that teens valued both the social features of the app and any "free stuff" or rewards it provided.