Chances are, if you’re a college student, you’ve had some experience with an online identity service.

Maybe you call it a social networking site. Social media. A waste of time.

However you choose to categorize them, services like Facebook and Twitter are forces to be reckoned with — and Google Buzz is throwing its hat into the ring.

At this point, it shouldn’t be news that your online profiles play a huge part in the way others perceive you.

Who are you on Facebook? Did you know that, with more than 400 million active users, if Facebook were a country it would be the world’s fourth largest? Does that make a difference in the way you want your profile to appear?

Twitter, on the other hand, processes 50 million tweets per day.

With the exception of Facebook rolling out some Twitter-like features in the past year, the two networks seem to coexist and serve different — not necessarily competitive — purposes.

Google Buzz, on the other hand, is a little harder to categorize.

Google unveiled the service on Feb. 9, announcing that Buzz would be automatically integrated into Gmail users’ existing accounts.

That’s approximately 175 million built-in Buzz users. Genius.

It looks like Google has thrown the first punch in what is bound to become a schoolyard brawl between Google and its most likely rival, Facebook.

But perhaps it was more of a light shove.

After all, Buzz didn’t have a perfect start. Many Gmail users were unhappy with being involuntarily thrown into the service, especially because of an early — since-deleted — feature that automatically set users up to “follow” their most frequent Gmail contacts.

Plenty of us found ourselves wondering if we really need yet another social network — although Buzz does allow integration with Twitter, Piacsa and Flickr, but interestingly, not Facebook.

It could be a while before we know how successful Buzz is. But here’s one thing we do know.

These companies are vying for our identities.

There could — quite likely — come a day when you need just one online identity to login to any site you visit.

Google and Facebook both want to be that identity.

Facebook Connect already serves this purpose to some degree. Using an authentication method, you can connect your Facebook account to any partner Web site, effectively transferring your entire Facebook identity to that site.

Sometimes, Facebook might decide to sign you in without asking. If you visit www.vancouver2010.com on a computer that has your Facebook login information stored and visit the page for an Olympic event, a Facebook feed will pop up on the side. Typing into the provided box will post an update to the feed, along with your profile.

It’s easy to be distracted by how cool these features will be — just think of the time one centralized online identity would save.

But we’re not sold yet. Something about allowing all of our personal data to be held by one social networking service and transferred with ease at the click of a button seems a little Big Brother-ish.

So, we’ll enjoy these technologies. But we’ll keep our guard up. And we suggest you remain cautious, too.