With the release of a new album approaching, Kanye West is making sure he's up to date with the social networking sites. He joined Twitter Wednesday, one day after going to the offices of Facebook, in Palo Alto, California, to preview some of his new material. Videos of him rapping a cappella while standing on a conference table have been posted on YouTube. On his website afterward, West posted a letter to Facebook, thanking the staff for their support: “Your energy was a gift so electric, so genuine, that it really helped me give my best.” West's new as-of-yet untitled album is expected to be released Sept. 14.