Greetings,
For a long time I had the following idea in mind:

Assuming I like a particular song or artist. There should be a source that would suggest me other songs or artists I might also like.

Today I found out infact such a website exists. Here is the link:

http://www.pandora.com/

It is prettt straightforward and free. Enter a song name or artist name and you start listening to smillar artists or songs. It is like listening to a private radio channel. The sound quality is good and these are full lenght songs.

I tried it, interesting database as far as I could hear. Shame you have to register after a couple of songs though, and registering is only for US citizens

So far for my empirical research

I just put five zeros as US zip code. Registration is very easy. You simply put a username, password, e-mail and any US Zip code and there you go. No activation via e-mail or whatsoever.

Ahaaa! Of course! I didn't try that.

Gonna continue the research then