unveiled an initiative called Facebook Platform, inviting third-party software makers to create programs for the service and to make money on advertising alongside them. The announcement stimulated the creation of hundreds of new features or "social applications" on Facebook , from games to new music and photo sharing tools, which had the effect of further turbo-charging activity on the site.
As a result, estimates of Facebook's valuation soared during the summer of 2007. In October, Microsoft outbid its archrival Google to invest $240 million for a 1.6 percent stake in Facebook, which valued the company at a startlingly rich $15 billion.
Facebook's rise has been marked by several controversies. Three other Harvard students maintain that they came up with the original idea and that Mr. Zuckerberg, whom they had hired to write code for the site, stole the idea and surreptitiously created a rival company. Facebook has denied the allegations; a lawsuit is pending.
Another Harvard classmate, Aaron Greenspan, asserts that he created the underlying architecture for both companies, but has declined to enter the legal fray .
In November 2007, Facebook again created a storm when it announced a new advertising system called Beacon, in which users' purchases or activities on some 40 partner sites were broadcast to their Facebook friends. Some users claimed that they were not adequately warned about the feature, and the political activist group MoveOn.org organized a protest group on Facebook, which attracted more than 70,000 members.
In December, Facebook capitulated to a key demand of the protesters by offering users an easy way to decline to take part in Beacon.
In February 2009, when Facebook updated its terms, it deleted a provision that said users could remove their content at any time, at which time the license would expire. Further, it added new language that said Facebook would retain users� content and licenses after an account was terminated.
After a wave of protests from its users, Facebook said that it would withdraw changes to its terms of
