Myspace is a social-networking website that many Stanford students use. It is not nearly as popular on campus as Facebook.
Myspace has the stigma of being "so high school" and "Facebook for non-college students," but since Facebook opened to the public last year, the two sites offer similar exclusiveness.
Myspace is also known for its open design policy - that is, users can customize their pages to the extreme using CSS or HTML. This tends to make most Myspace pages either illegible or incredibly annoying. Watch out for bad music automatically playing on many user pages, too.
Myspace cultivates a strong music-based community, offering an outlet for new bands to distribute music for free. Many Stanford-based bands have Myspace pages that they use to announce concerts and advertise the band and its music.