Foursquare is edging even deeper into Yelp territory. Today the check-in social network announced that it is launching a 10-point rating system for local businesses with its iOS app update.

Sound familiar? That's because it's basically Yelp's business model. However, Foursquare said that what it's introducing is "a lot different from the other types of ratings you see today."

"Instead of other sites where every place gets 3.5 stars, we come up with our scores using the same Foursquare magic that powers Explore," the company wrote in a blog post today. "We look at signals like tips, likes, dislikes, popularity, loyalty, local expertise, and nearly 3 billion check-ins from over 25 million people worldwide."

The way the ratings system works is iOS users can go into the Explore section of Foursquare's app and see or add a score from 1 to 10 next to the name of a restaurant, bar, boutique, or whatever else is listed. Besides just checking out scores on the app, users can also see ratings online at Foursquare's Web site.

Over the past few months, Foursquare has been working to become more of a local search engine than just a check-in social network. In October, it launched its new Web site, which is open to non-members and has a prominent search box. The company has also been in the process of adding more specific information to its listings, like when a place is open and prices.

While it seems that Foursquare is treading on Yelp territory, the competition goes both ways. Yelp revamped its site in August to highlight social connections. The new feature included a news feed of sorts that shows friends' activity on the site, including comments, check-ins, photos, and tips. Today, Yelp also rolled out in-app restaurant menus for its mobile users.