Free All Music is a company, based in Atlanta, which still reckons ad-supported MP3 downloads is a viable business model. The company thinks it can do better than Spiralfrog and its similar proposition, which disappeared last year, by making users pick their own adverts.

On the site, you pick which MP3 you want, then you choose a sponsor to "buy" if for you. The site then displays a 15-18 second video ad, and once that's complete you'll be able to download the file - a DRM-free 256kbps MP3 file.

The advertiser will then be able to use your username and purchase info in its own advertising around the web - so it could display to the world that you just picked up Lady Gaga's "Poker Face". Free All Music can therefore sell multiple adverts on each downloaded file.

The catch is that you can only download as much as advertisers are willing to pay for. If no-one's prepared to stump up for a track then you won't be getting it. The company is, at launch, aiming for "typical iTunes behaviour" - 15 songs every 3 months.

How well that'll gel with the typical audience for music startups - which tend to be both big music fans and big music consumers, not iTunes users - remains to be seen. If the company can get more advertising, then the song allowance will increase.

What everything hinges on, though, is catalogue. It's widely agreed that one of the reasons for Spotify's early success was the strength of its catalogue and the ease of use of the software. At the moment Free All Music only has one major label signed up.

Also, given the wealth of other sites offering semi-legal free MP3s - even before you start looking at file sharing networks - it seems like it'll be tough for Free All Music to gain a foothold. We'll keep you posted of the company's progress.