Facebook claimed today its user numbers have risen to 300 million worldwide and that it is now at break even.

The world's largest social networking site has announced it is generating enough cash to cover operating and expansion costs and that it can now call itself a viable business.

Analysts immediately began speculating that Facebook is warming up for what would be the most high-profile stockmarket flotation in years, as it attempts to rebut questions about its business model.

Facebook chief executive Mark Zuckerberg said on the company's website that Facebook reached its goal of being cash-flow positive in its most recently ended quarter. Facebook had previously projected reaching the target sometime in 2010.

"This is important to us because it sets Facebook up to be a strong independent service for the long term," said Zuckerberg in the blog.

Facebook's stratospheric rise - its user numbers have tripled from 100 million a year ago -means its popularity is now said to rival established powerhouses of the web like Google and Yahoo.

Earlier this year Facebook took a $200 million (£121.3 million) investment from Russian investor Digital Sky Technologies in a deal that valued the company at $10 billion.