Core Facebook investor Marc Andreessen believes that Facebook will easily clear $500 million in revenue in 2009 and "billions" annually in 2014, reports Reuters . "This calendar year they'll do over $500 million," Andreessen said in an interview, noting that Facebook has more than 225 million users, so revenue per user is still small. "If they pushed the throttle forward on monetization they would be doing more than a billion this year," said Andreessen, who made the cover of Time Magazine as founder of the world's first Web browser company, Netscape. "There's every reason to expect in my view that the thing can be doing billions in revenue five years from now," Andreessen said. Barring sudden cataclysmic disruption or legal action, Andreessen's forecast seems pretty reasonable to me considering that 1) upwards of 1 billion more humans may well be online by then, 2) server costs will continue shrink, and 3) CPM rates will c...