September 2009 should go down as an historic turning point for social media, as Facebook is now bringing more money in than it is paying out. That doesn't necessarily mean that is is profitable yet, as Douglas MacMillan writes in BusinessWeek : Rather, the cash it generates from advertising and other forms of revenue now exceed the cost of servers and other capital expenditures required to keep Facebook running. One-time costs, like the reported $50 million acquisition of Friendfeed last month, and operational expenses like personnel, are not included in this equation. Outside investments in the company, like the $200 million it raised from Digital Sky Technologies in May, are not accounted for either. Facebook has never disclosed its revenues, but board member Marc Andreessen recently told Rueters that the site is on track to generate over $500 million in revenues this year. The same day it announced its cash flow milestone, Facebook said it has added 50 million users in the past two months — bringing its total user base to 300 million and its signup rate to roughly 806,000 users per day. That’s a huge amount of traffic to support, and the site’s accumulating stockpile of photos, videos, and other content requires an ever greater number of expensive servers. This was a serious problem for Facebook as recently as March, when my colleague Spencer Ante reported that it was seeking $100 million in debt financing directly related to server costs. Now, it appears that economies of scale are working in the company’s favor: the more members it attracts, the less it has to pay to support each one. Read the full article here . And listen to, or download, Marketplace radio's coverage of the news here .