Let’s say you enjoy listening Justin Timberlake’ tunes. Just visit Last.fm, type in the name in the “Start Listening with Last Fm..” and in a matter of seconds you will have access to a list of Timberlake’s tunes and to similar artists. And, as any site born in the Web 2.0 era, Last.fm has also a strong component of social networking. 

Anyway, from today, Last.fm’s 20 million unique monthly users will enjoy free, global, on-demand access to the largest licensed catalogue of music built on partnerships with all four major record labels - including Universal Music Group, Sony/BMG, Warner and EMI.

Besides the Big Fours, Last.fm has signed a similar deal with 150,000 independent labels and artists.

But there is also a limit. As Last.fm explained, all tracks can be streamed for free up to three times each. After that, the listener will be invited to buy the song from iTunes, Amazon or 7 Digital.

Last.fm’s service will be advertiser supported, allowing clients many unique opportunities to reach a highly targeted and engaged audience.

"We're giving the listener free access to what is basically the best jukebox in the world. The ability to dip into such a uniquely broad catalogue from your laptop, home or office computer, and listen to whatever you want for free represents a new way of consuming music that in turn might change the way you listen to music,” said Martin Stiksel, Last.fm co-founder.

But Last.fm has bigger ambitions than being just a music platform. The website unveiled quite a revolutionary service, called "Artist Royalty".

The artists who will enroll in this service will receive payment, directly from Last.fm, every time one of their tracks is played.

“For the first time, anyone can upload tracks and get paid when those tracks are played. It's a whole different model -- one that benefits the artists, labels and advertisers - but most of all the listeners," explained Last.fm's other co-founder, Felix Miller.

Lately, facing the decline of CD sales, the music companies are looking to new ways to promote and sell their music.

Last year, Universal Music signed a deal with Imeem, a social networking service launched in 2004, who claims to have over 19 million users every month. According to the terms of the agreement, Imeem users will be to listen to the free songs provided by the major music label. The users will only be able to store music on personal pages, but Imeem offers direct links to Apple’s iTunes store or Amazon.com for those who wish to download and store them on their computers or MP3 players.

Imeem has now deals with the other three major labels as well as a large number of independent labels.