Given that more than two billion people use Facebook, you'd think that all these social media devotees would have developed a near infinite number of ways to use the site, from sharing baby pictures and online shopping, to organizing political rallies or touting their latest entrepreneurial endeavor.

But according to a new study out of Brigham Young University, despite the astonishing diversity of approaches to social media, all Facebook users can actually be sorted into only four major types.

By asking a sample of users to rate how strongly they identified with a variety of statements about Facebook and then conducting follow-up interviews, the research team claims they were able to short all participants into only four baskets.

Even though study leader Tom Robinson admits there is some overlap in the online behavior exhibited by subjects, in the end one label fit everyone best. "Everybody we've talked to will say, 'I'm part of this and part of this, but I'm mostly this,'" Robinson said.

1. Relationship builders

For this type of user Facebook is primarily about cementing real-life friendships and building closer personal ties with people they actually know and see. "They use it as an extension of their real life," Robinson commented. Relationship builders tended to agree with statements like, "Facebook helps me to express love to my family and lets my family express love to me."

2. Town criers

Town criers are the news junkies of Facebook who always know -- and share -- what's going on in the world and in their community. They "want to inform everybody about what's going on," Robinson says, so they're continually pushing out information.

You can identify them by the steady stream of articles and announcements in their stream, and the relative dearth of personal information and interactions revealed on their profile pages. "I don't talk to my family on Facebook," one town crier told the researchers. "They are more important than that."

3. Selfies

For this type, Facebook is primarily a self-promotion or self-validation tool. Rather than aiming to strengthen ties with others like relationship builders, or be seen as the definitive source for information like town criers, selfies' purpose on Facebook is collecting likes and comments. They tend to agree with statements like, "The more 'like' notification alarms I receive, the more I feel approved by my peers." They're also not terribly interested in authenticity.

Selfies use Facebook "to present an image of themselves, whether it's accurate or not," notes study co-author Kris Boyle.

4. Window shoppers

This group of more reluctant Facebook users feels obligated to be on the site to keep up with others but isn't much interested in sharing details of their own lives. "It's the social-media equivalent of people watching," according to another study co-author Clark Callahan. They're also not averse to a little bit of harmless Facebook stalking, using the site as a tool to round up information on potential dates, job candidates and the like.

A few caveats

While it's fun to compare these findings with your own Facebook behavior, or use the results as a springboard to think more deeply about how you use the site, it should be noted that this is hardly a definitive global survey of social media use.

The researchers only talked to 48 users (though they claim they used rigorous statistical techniques so that their conclusions are still valid despite the tiny sample size) and all of them were American, so it's entirely possible that elsewhere in the world people are using Facebook in other, still unexplored ways.

Which of these types to you identify most strongly with?