Facebook, the incredibly ubiquitous social networking site, made its latest move in the struggle to make a buck on Wednesday. The company is calling its latest breed of marketing “social ads,” a system where your own expressed brand preferences and Internet browsing habits and even your very identity are used to pitch goods and services right back to you and your friends!

While I’m all in favor of the little guy — if Facebook can even be called that anymore — cashing in on its own success, I hope I’m not the only one that’s more than a little disturbed at privacy-invading advertisements.

Three new features available through Facebook make these social ads possible, all of which are built on the core Facebook platform and the Facebook Application Programming Interface. These are “Facebook Pages,” a program for companies and organizations to create their own mini-sites within Facebook, “Beacon,” a new extension of the API that allows Facebook to harvest information about user actions from participating external sites and the News Feed/Mini Feed feature that was introduced last year.

Social Ads collect information about you in two ways, according to the keynote delivered by CEO Mark Zuckerberg and further explained by an official blog post by Leah Pearlman, the product manager for Facebook Ads. First, you will be able to interact with companies’ sponsored Facebook pages and applications, thus declaring your undying allegiance to Pepsi Cola, for example. This was in many ways already happening under the old, pre-social ads API. Bribed with the promise of free iTunes songs and merchandise, I myself joined the “Apple Students” group. Facebook Pages may extend this functionality even further, but it’s little more than a minor twist on the existing theme of the commercialization of Facebook profiles.

The second method is what really makes this whole thing interesting, however. Through Facebook’s new Beacon service, any website will be able to feed your actions on their site back to Facebook.

“For example, adding the first season of Buffy the Vampire Slayer to your queue on Blockbuster.com might be something you want your friends to know about, so you can have a marathon,” Pearlman helpfully explained.

I wouldn’t want my entire social network to miss out on my addiction to bad ’90s television shows. And under the new system, there’s no way they ever would, as Facebook will happily slap an ad for Blockbuster straight on my friends’ news feeds. This all helps Facebook and its parters make money because, after all, as Zuckerberg extolls, “nothing influences a person more than a recommendation from a trusted friend.”

This may seem all fine and good to you, but what about the next time you’re on Blockbuster, after you’ve given them permission to report your renting habits back to Facebook? Just as Beacon will gladly proclaim your love for the latest popular sitcom, it will also publish your addiction to daytime soap operas. And maybe now, at this moment in time, that’s just not something you were prepared to share with the entire world (by the way, who here is Facebook friends with at least one professor? A boss at work?)

The problem is exacerbated on other types of sites, such as NYTimes.com, the online home of The New York Times. As the Web Editor for The Sun, I know as well as anyone that in the online news business links equal money. Even from the common user’s neck of the woods, sharing news stories is a really great feature; my own Mini Feed is little more than a litany of the latest articles from my favorite papers and blogs. But let’s say John uses the Internet to indulge a buried curiosity on the history of infectious diseases. John could spend entire days browsing The Times’s vast 150 year-long digital archives for articles on this one topic. But does John really want a badge to pop up on his friends’ news feeds stating, “John spent the better part of yesterday reading about Staphylococcus aureus” along with a picture of John passed out on the floor from last week’s party?

Ultimately, I don’t expect social ads to cause an exodus from Facebook en masse; in all likelihood there will be a great Facebook-centered hubbub about it, and then it will pass quietly into the night. (To paraphase Stephen Colbert from two weeks ago, “What is wrong with [us] people?”) However, Facebook’s new ads make the common-sense policy for social networking ring even truer: be careful what you put on the Internet, because chances are someone will see it that you’ll regret. And market it, of course.