Facebook has acquired a broad set of patents on social networking covering the basic functions of just aboutany social app, ranging from friend lists to the news feed.

The patents were acquired from Friendster, which has been awarded a wide array of social networking patents over the last decade. According to VentureBeat, there are 18 patents in all; GigaOm reports the price of the portfolio was $40 million.

As with many technology patents, the Facebook patents are rather broad (some might say ridiculously obvious, too). For example, one of the patents, as we wrote back in 2006, covers “a system, method, and apparatus for connecting users in an online computer system based on their relationships within social networks.” Another covers the slightly more innovative concept of photo tagging.

For its part, Friendster didn’t do much in the way of enforcing its patent portfolio, even as it fell from prominence in the U.S. It remains to be seen what Facebook’s intentions are for its newly acquired IP, but the patents will certainly make it more challenging for others to go after the world’s biggest social networking site with claims of infringement –- at least on the core features of the product.

With numerous cases (and a movie) exploring the origins of Facebook, owning the basic patents that make social networking possible undoubtedly strengthens the company’s position.