Washington Post Co. Chairman Donald Graham is joining the board of Facebook Inc., connecting the popular Internet hangout with a media industry veteran.

The addition of Graham, announced Thursday, marks another step in Facebook's maturation since Mark Zuckerberg started the company in a Harvard University dorm room less than five years ago.

Now based in Palo Alto, privately held Facebook has about 130 million members who use the Web site to share information with their friends and family.

Zuckerberg, 24, has been bringing in more experienced leaders as he tries to capitalize on Facebook's massive following. This year, he hired one of Google Inc.'s top executives, Sheryl Sandberg, as Facebook's chief operating officer and persuaded Web browser pioneer Marc Andreessen to join the board.

Graham becomes the first chief executive from a company that belongs to the Standard & Poor's 500 stock index to join Facebook's board. Besides Zuckerberg and Andreessen, Facebook's other directors are venture capitalists Jim Breyer and Peter Thiel, the former CEO of online payment service PayPal.