Over 500 million people have joined the social networking site Facebook, the company's founder said.
It means almost 8% of the world's population use the tool to connect with friends, family and colleagues.
The "important milestone" comes only months after Facebook announced that 400 million users were active on the site.
The company's chief executive, Mark Zuckerberg, said: "As of this morning, 500 million people all around the world are actively using Facebook to stay connected with their friends and the people around them.
"This is an important milestone for all of you who have helped spread Facebook around the world. Now a lot more people have the opportunity to stay connected with the people they care about."
Recently Mr Zuckerberg said the company is likely to reach the billion-user mark but technology bloggers are sceptical and have suggested the current figure may be a peak.