(CNN) -- Like a lot of people, Anna Owens began using MySpace more than four years ago to keep in touch with friends who weren't in college. Our real-world friendships are often a reflection of who we connect with online, experts say. But soon she felt too old for the social-networking site, and the customizable pages with music that were fun at first began to annoy her. By the time she graduated from the University of Puget Sound, Owens' classmates weren't on MySpace -- they were on Facebook. Throughout graduate school and beyond, as her network began to expand, Owens ceased using MySpace altogether. Facebook had come to represent the whole of her social and professional universe.
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A recent Nielsen study finds class differences between online social networks
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Wealthier people are more likely to use Facebook; the less affluent, MySpace
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Almost 38 percent of LinkedIn users earn more than $100,000 a year
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A researcher found that college students tended to self-segregate online
"Blue-collar, part-time workers might like the appeal of @placeholder more -- it definitely depends on who you meet and what they use; that's what motivates people to join and stay interested."
On the other end of the spectrum, 37 percent of @placeholder members earn less than $50,000 annually, compared with about 28 percent of Facebook users.