@Twitter: we'd really like to buy you

The founders of Twitter, the micro-blogging service that has become a media sensation this year, have opened talks with Google about a tie-up, and speculation is rampant that they could be prepared to sell out to the internet goliath.

Rumours of a takeover, which would turn its three thirtysomething founders into millionaires many times over, were sparked by a report on the Silicon Valley blog TechCrunch, and spread round the internet in the time it takes to type 140 characters. This is the limit for a single "tweet", the name given to a posting on the Twitter service, which is used by 7 million people in the US alone.

Twitter was valued at $250m when it raised money earlier this year, and its explosive growth suggests that Google could be willing to pay a multiple of that figure. In the UK, where the comedian Stephen Fry is the most famous prolific tweeter, its users have grown tenfold over the past year, while celebrities, politicians and businesses are increasingly using the service as a way of communicating with the public.

Biz Stone, Twitter's co-founder and creative director, said yesterday that the team was committed to building "a profitable independent company – and we're just getting started". But he added: "It should come as no surprise that Twitter engages in discussions with other companies regularly and on a variety of subjects." Google did not comment.

Twitter was founded two years ago by a trio of Silicon Valley entrepreneurs who hatched the idea of allowing people to share text-message-length status updates on the internet and phones. Jack Dorsey, who is now Twitter's chairman, Evan Williams and Biz Stone stand to share a huge windfall when it is sold.

A sale to Google is the ultimate cash-in for entrepreneurs in the technology industry. YouTube was bought by Google for $1.65bn in 2006, despite never having made a profit. Outsiders have been mystified, too, about how Twitter will make money, since its service is free.