The rumors have been floating around for a while, and now Mike Arrington is reporting that Marc Andreessen is going to join Facebook's board of directors. (Kara Swisher had the original news break back in May.)
Best known as the founder of Netscape, Andreessen these days is involved with Ning, which supplies a platform for "white label" social networks that you can brand as your own.
We'll try later to get more clarity about how all of this is supposed to shake out.
If the move indeed goes down, Facebook will pick up a plugged-in entrepreneur who can share war stories about the successes and mistakes that defined Netscape's relatively brief moment in the sun before Microsoft got serious about competing. The good news for Mark Zuckerberg is that Facebook doesn't (yet) face a rival on that scale.