Hey, Waldo, pretty soon your Facebook friends will know more than what’s on your mind and what you Like.

They’ll also know exactly where you are.

This month, Facebook is expected to roll out location-based functionality that will allow users to append their location to their status updates.

It’s pretty easy to picture: hit your local pub, coffee shop, sushi bar, post a relevant update, and suddenly everyone knows where you are and can act accordingly — whether that means coming to join you, avoiding you or robbing your house depends on your relationship.

Joking aside, this is bad news for independent location-based mobile apps like Foursquare and Gowalla. Though these apps have been all over the media lately, in terms of scale, they’re nowhere near the size or ubiquity of Facebook.

With half a billion users and growing, the World’s Biggest Social Network is ripe for location integration.

And marketers are viewing it as a ripe opportunity. Now, Facebook is being coy about whether or not sponsorships will come into play with the location feature. A spokesman told AdAge, “”We may consider working with marketers to enhance the experience in the future, but have no plans to so do at launch.” (They said much the same thing to TechCrunch as well.)

But at the same time, Facebook is already planning to allow McDonald’s a piece of the location McPie.

But the great thing about social media is that, for businesses, leveraging platforms like Facebook, Twitter and Foursquare connect with customers remains essentially free. Just as we’ve encouraged you business owners to take advantage of Foursquare, we urge you to sit up and take notice of this.

With Facebook adding a location feature, the opportunity for organic, word-of-mouth-style viral marketing is huge for any business with a physical store.

Car washes, museums, grocery stores, mom-and-pop dry cleaners, hot dog carts — there’s basically no one who doesn’t stand to benefit from this.

For users, just make sure you don’t announce your location when you don’t want to be found.

Right, Waldo?