Think everybody and their uncle is on Facebook? Think again.

A new study from Northwestern University finds that college students’ choice of social networking sites is related to race, ethnicity and parents’ education.

The study found that Facebook is the social networking site of choice for white students, that Hispanic students prefer MySpace and that Asian and Asian-American students are least likely to use MySpace.

While prodigious users of Facebook, Asian and Asian-American students were found to use the less popular social network sites Xanga and Friendster more than students from other ethnic groups. It found no statistically significant social networking choices for black students.

That finding is inconsistent with ideas about the Web’s potential to improve people’s lives by sidestepping physical constraints. “In this case, it is the already constrained students who miss out on the Web’s potential benefit,” one of the study’s authors said.

What’s more, it suggests that social networking sites actually may contribute to a two-tier social system if, as the study suggests, people who already are interacting less with others on campus are also doing less interacting online.

It makes you wonder — why aren’t these social networking websites reflecting the diversity of the world? Two possibilities, out of many, come to mind.

One possible explanation is that of the “snowball effect” — for whatever reasons, certain sites attracted people of a certain ethnic background to begin with. If your friends are on Site X, then you’re more likely to join Site X, regardless of the site’s overall popularity amongst the general Internet population.

A second possible explanation is that certain social networking site’s design and feature set may be more appealing to one ethnic group, but not to another. For instance, if Myspace allows total customization of my profile page (which it does) and Facebook doesn’t (which it doesn’t), that may be more appealing to a certain ethnic group and attract more people from that group.

The study didn’t examine possible explanations for their findings, so these are just my educated guesses based upon previous experience and research.

Read the full article: Choice of On-line Social Networks Influenced by Ethnicity