US micro-blogging service Twitter said on Friday that it has 200 million users worldwide as it marked the fifth anniversary of its public debut.
President Barack Obama, the British Royal Family, actor Stephen Fry and Lady Gaga have all signed up.
Twitter allows its users to communicate in short message of just 140 characters, known as tweets.
An estimated 1.6 billion tweets are sent each day.
Bloomberg reported on July 6 that the San Francisco-based start-up was in talks with investors to secure new financing.
The report said the financing would value the site at nearly five billion euros.
Twitter has declined to comment on the story.