facebook/myspace compare and also to linkened/plaxo

Facebook is a network for friends,family, classmates more to only people you know and allow . People looking for professional careers.  My space is for people looking for creative careers, and is a more open view to anyone's profile.  More college students are on facebook and more high school students are on my space. These two site are more for socializing than linkedin and plaxo which are geared toward the business networking.