According to social media expert Mashable, in February of 2009, Facebook officially overtook Myspace as the #1 social networking site on the web. While Myspace is in a comfortable second place, Twitter is quickly gaining support in third. These statistics only beg the question that’s been asked a million times since these sites were first launched: why do people choose one social networking site over another?

When I first joined Facebook in 2004, it was only available to college students. Because I also had friends who weren’t in college, I got a Myspace to keep up with them. Eventually, I found that my visits to Myspace became less and less frequent while my visits to Facebook did just the opposite. There were quite a few reasons for this. First, my friends eventually all migrated to Facebook when it became available for them and so there was no need for Myspace. Then there were creepy messages I kept receiving from guys I didn’t know. Then Myspace started allowing people to add all these extra features to their profiles like music, videos, pictures and designs. That was fine and dandy and even pretty cool at first, but a lot of people went a little overboard and looking at their profiles was more than annoying. By the way, if it takes 5 minutes for your Myspace profile to load, you need to tone it down.  More than anything, though, I just felt like I had more in common with my fellow Facebook peers.

Earlier this month, published this article that attempted to explain this phenomenon a little better. This article takes the “big 3,” Facebook, Myspace, and Twitter, as well as LinkedIn, and breaks them down into their respective demographics. The results are interesting to say the least. In essence, the article suggested a class divide between Facebook and Myspace. Market research from Nielsen Claritas found that the more affluent demographic is 25% more likely to use Facebook while the less affluent demographic is 37% more likely to use Myspace. The findings factor in income as well as neighborhoods in which these demographics live. For example, Myspace users tend to live in blue-collar, middle-class neighborhoods while Facebook users tend to live in upscale suburbs. Sites like LinkedIn and Twitter also provide interesting data with even more affluent users. An estimated 38% of LinkedIn users had an annual income of more than $100,000.

What does this all mean? Well, one theory is that social networks not only mirror real life, but also magnify it. In other words, the peers you associate with in real life will most likely be the peers you associate with on your social network. If most of your peers are in a particular social network, that’s most likely the one you’ll choose. Now this isn’t always the case. Some people just like certain features of one site better than another. If you’re a music buff, for example, you may choose Myspace to listen to your favorite bands, whereas if you’re job hunting, you might choose LinkedIn. There’s also the influence that the origin of these sites have had on the people who join them. As I mentioned above, when Facebook first came out, it was only exclusive to college students, so it shouldn’t really be a surprise that a lot of its members are educated. Still, we can’t deny the obvious self-segregation that’s happening. Is it a bad thing? I think that’s a matter of opinion. I’ll say this, though: it sure does make our jobs as marketers a little easier when trying to appeal to a specific audience, and that’s a good thing.