MySpace's New Rivals Are Winning Friends - WSJ.com
Lists Piczo (most popular site in Canada), XuQa.com, Hi5.com (with a built-in music player), and Sconex.com (for high school kids).
It's going to be very hard to make any social networking site sticky. By definition, these sites make it easy for you to talk with your friends -- and mobilize them all to another site if you want.
A more interesting business, I think, is something truly complementary to Myspace. What if MySpace were a platform, with an API, and you could build sites that preserve some of your identity at Myspace but allow a richer experience targeted say, to kids who like bugs, or for that matter, moms who like politics.