Facebook has an estimated 250million users worldwide
Facebook has threatened legal action against a service that sells friends on the social networking site.
It said it would take the action against marketing firm USocial unless it stopped violating Facebook's rights.
It also wanted USocial to stop helping members break the site's terms and conditions, specifically letting people profit from their profile.
In response, USocial agreed to a change in its practices but would not shut down its service.
Facebook sent Cease and Desist letters to USocial claiming that the way the marketing firm operates violates its rights by sending spam, using web tools to harvest pages, getting login names and by accessing accounts that did not belong to the marketing firm.
Customers of USocial use it to boost follower and friend numbers on social network sites such as Facebook and Twitter.
On micro-blogging site Twitter, followers can be bought in blocks starting at £53 for 1,000. The biggest block USocial is selling is 100,000 people.
USocial defended itself against Facebook's claims, saying that it did not spam users or use web tools to gather information about profiles.
However, in response to the legal letters, USocial said it would delete the login information it had collected and broadly stop offering to sell Facebook friends. It also put a notice on its site saying it was not affiliated with Facebook.
However, it said, there was "possibility" that it would resell the service in the future. If it was to re-start the service it said it would let Facebook know beforehand.