Mixcloud, an online radio startup based in London, has opened its doors to the public after an extended private test period. Its founders are a couple of DJs from Cambridge University who found it difficult to connect online radio providers to their listeners.

So they built Mixcloud to try and improve the situation, saying that their vision is to "build the YouTube of radio - a definitive online platform for on-demand radio shows, from music to talk". They describe the concept as "Cloud Radio" - because all the shows are accessible on-demand anywhere.

It has content from Diesel Radio, Mixmag, Chris Coco, and over a thousand other DJs, with the content leaning towards club music and DJs, but the founders say that they're "in discussions" with providers for other genres of music, as well as talk programmes.

You can search for shows by genre, by tag, by artist and also by user, and you can set up a profile and then follow other users to see what they're up to. When you do that, you'll also get a Facebook-style activity stream at the bottom of your homepage.

What's most important is that the artists get paid - unlike traditional podcasting, Mixcloud will pay royalties to PRS for Music for any songs contained within its uploaded shows. It's not clear yet how it plans to make money - perhaps by offering its back end to radio stations and DJs so they can brand their own content individually and push it out there.

You can embed individual shows, like this:

At the moment, that content is limited to a maximum 100MB MP3 mixes, but from our brief play with the functionality, it seems pretty effective at what it does. How well it achieves its goal of being the YouTube of radio will depend on how quickly it's able to build its community - at the moment there isn't a whole heap of content on there.

But there isn't another service out there that duplicates what Mixcloud does, so if it can crack that all-important community, then it could become as successful as that other famous London digital music startup - Last.fm. Time will tell.