The company will allow users to register any name they like after the main Facebook address, such as: www.facebook.com/nike. This raises the prospect of individuals registering names that are trade marked to companies or organisations.
The company has put in place a pre-registration process by which companies can list their trade marks and bar others from registering them as names before registration begins.
Trade mark owners can fill in a form listing the marks that they want barred from registration. If a name has already been taken by the time the company finds out, they can fill in an IP infringement form that alerts Facebook to the problem.
"[We want] to help our users avoid potential disputes concerning usernames that may be protected by intellectual property rights," said a company explanation of its actions on its website. "In order to do that, we have encouraged rights owners to contact us if they want to reserve/protect certain names."
John MacKenzie, an intellectual property specialist at Pinsent Masons, the law firm behind OUT-LAW.COM, said that Facebook's actions were a sensible response to an obvious problem.
"Facebook is one of the world's biggest communities, with a growing commercial community," he said. "Increasingly consumers will look to those communities for reviews of products and even to buy products."
MacKenzie said that the practice of registering someone's trade mark as a Facebook name is analogous to cybersquatting on web domain names.
"This is the same as if someone registers any domain name with another company's trade mark in it. In the UK there is case law deciding that just holding the domain can amount to unlawful conduct, and can be stopped," said MacKenzie.
Facebook has taken other steps to combat opportunistic name-squatting. It will not allow anyone who registers a profile after it announced the name feature to apply for a name in the first place.
"Eligibility is limited to anyone who joined Facebook before usernames were publicly announced," it said. "This decision was made to prevent people from creating new accounts just to take advantage of reserving a username."
It is also restricting people's ability to pass a username on, which will also help to stop trade in desirable names.
"Once you have claimed a username by clicking the "Set Username" button, it is not possible to edit it, or to transfer your username to a different account on Facebook. Additionally, when an account is removed from the site, its username will not be made available," it said.
There is no fee for submitting a trade mark to Facebook's pre-registration process.
Editor's note, 12/06/2009: This article initially suggested that Facebook allowed users to register domain names. As an eagle-eyed reader pointed out, that is inaccurate: it only allows them to register URLs. The domain name is still facebook.com. Apologies for the error.