Why World of Warcraft is the most played mmorpg in the world?

It's a great game, but I get tired of it really fast.
My friends too does.

So why there are so many people playing it?
It is not even free! There are much more mmorpg free to play, some even in...

Where can I download legal music?

Then? Does anyone knows?

Because, I know a lot of sites, but all of them are illegal contents.
Like kazaa or even Limewire.

Is there any p2p legal music downloader?

Thanks