The social-networking site is updating its Statement of Rights and Responsibilities — if approved, account holders must agree not to use the words “Face,” “Poke,” or “Book.”

Individual privacy is a hot topic in the social-networking world right now. But have people thought about privacy of the companies, such as protection of their brand, logo, and trademarks?

This is something Facebook is looking into. In the recent revisions (PDF) of its Statement of Rights and Responsibilities, the social-networking site is now saying that account holders “will not use” the word “Book.”

That’s right, Facebook is trying to trademark the word “Book.”

If these revisions are approved, when users sign onto Facebook they will be agreeing not to use that word if they log into their account. However, this change is actually only a subtle difference from the list of terms account holders cannot use under the current Statement of Rights and Responsibilities.

“You will not use our copyrights or trademarks (including Facebook, the Facebook and F Logos, FB, Face, Poke, Wall and 32665), or any confusingly similar marks, without our written permission,” Facebook’s current Statement of Rights and Responsibilities says.

The new revisions include the word “Book” and take out “32665” (which is the number to text if Facebook users want to update their profile).

According to tech news site Ars Technica, which first reported this news, Facebook has 73 active trademarks listed by the U.S. Patent and Trademark Office, including the letter “F,” “Face,” “FB,” “Wall,” “Facepile,” and “Friendfeed.” “Book” is not yet on the list.

Facebook did not immediately respond to request for comment.