The marketing news this morning is covered by articles about a small informal study that said that Facebook and MySpace are very different sites with very different demographics despite both being social networking sites that are popular with the 15-25 age crowd. They say through their informal polling and surveys, they found that MySpace users tended to be kids who got jobs and started working right after high school, (think retail, restaurants, trades and family businesses) and they were a more ethnically diverse group. FaceBook was more a white bread hang out for college students and college grads (read higher salaries and more money to buy high end stuff). This is interesting to marketers trying to segment this young socially networked audience, but it isn’t a hard fast rule to what you will find on both these sites. I know a lot of college grads that use MySpace and Facebook. I also know some who only use MySpace. Facebook turned off a lot of people by requiring a university email address for registration until recently and a lot of people who had already graduated and given up their college email addresses couldn’t join, so they did friendster (blast from the past) , Orkut (what’s that?) and MySpace when it became hip. Likewise now, anyone can join Facebook so as time goes on it will only get more diverse ethnically, eductaionally and economically. So, there are a LOT of exceptions to these findings and I would do some actual testing to see if your product’s target demo graphic uses both sites before writing off one or the other too quickly.