Basically a music storage server and a streaming server at the same time. Just imagine, able to listen to your favourite collection of tunes anywhere on any computer with just an Internet access. Or even from your iPhone or Andrioid powered mobile phone. There is no need to bring a storage device around anymore. Just upload all your music onto their server and you are done. You can use their web-based media plyer to listen to your songs. Not only that, you can easily manage your music  through their interface as well. Overall, it seem to be a very good idea. If this works out, everyone can store and access their music online. This is indeed the future, where everything is stored and accessed online in the "cloud". Their plans start from 11GB to 151GB of storage. But for some audiophiles, even 151GB is not enough.