Last.fm connects users who share the same music tastes

The service, bought in May for $280m (£140m) by CBS Corporation, has signed a deal with the Sony BMG record label.

The partnership will give the web 2.0 service's 20 million users access to the entire Sony catalogue of music.

Started in 2002, the new deal will make Last.fm the largest web radio service the world, according to the company.

"We've always aimed to have everything ever recorded available to listen to on our site, and having access to Sony's collection of some of the world's most popular music takes us another huge step closer," said Martin Stiksel, co-founder of the service.

Last.fm allows users to connect with other listeners with similar music tastes, to custom-build their own radio stations and to watch music video clips.

The software also tracks what users play on their PC or MP3 player to make recommendations.

Thomas Hesse of Sony BMG said this was key in its decision to partner with the UK firm.

"The Last.fm streaming service will give our established artists a platform through which they can reach new audiences, and its unique recommendation system will provide our emerging artists with an important opportunity to build their fan base," he said.