That issue arose this afternoon, when theAssassin's Creed Facebook page began teasing a new entry in the series. Earlier in the day, the page urged gamers to "spread the word to reveal the next Assassin's Creed game" with a Flash application that allows for e-mail, Twitter, and Facebook reposting. The application then went down, then went back up again, and was then pulled--although it is still running solo.
The site also featured a teaser video that eager fans quickly uploaded to YouTube. It shows nothing in the way of gameplay, merely depicting some murky visuals with what appears to be some text in Arabic. Commenters translated the text as saying "Altaïr Ibn-La'Ahad," or "Altair, son of no one"--indicating the game could feature the original Assassin's Creed hero as its protagonist.
Additionally, an eagle-eyed NeoGAF poster did some digging and found a logo for "Assassin's Creed: Revelations." When asked about the validity of the title, Ubisoft declined comment.