Andreessen joins Facebook at a crucial time in its growth. Competitors MySpace and (increasingly) Google are gunning for control of the social graph, which may be the engine that drives the next big growth wave in advertising. Several early Facebook executives have left this year as the company has evolved, and new executives have taken their places. Zuckerberg needs a trusted guy in his corner to help him avoid missteps like the launch of Beacon last year, which has led to serious privacy concerns. Andreessen has fought similar battles in the past and won, and his counsel is clearly a competitive advantage.
This is an interesting move for Facebook as Andreesseen is a near-competitor with his social media startup Ning – yet he also brings significant startup and IPO experience with him to the Facebook board.