>during the period beginning in 2006 when teens began to flock to Facebook, teens' preference for either MySpace or Facebook appeared to fall along lines of race and class.<p>The obvious answer to this is that Facebook was closed to the general public until September 2006. In 2004 to early 2005, you had to be a college student at a top-30 or so school to be able to use Facebook. Throughout 2005, that loosened to all colleges. In Sept. 2005, they opened to "invited" highschoolers.<p>So let's flash-forward to September 25, 2006. MySpace's population is drawn from the general public, and Facebook's population is "college students, recent college grads from top schools, and high schoolers who are friends with college students". The next day, Facebook opens to everyone. If you don't have many friends who are "college students, recent college grads from top schools, and high schoolers who are friends with college students", you have little incentive to join Facebook.