Scribd.com ?

[BOBOT]

I was searching for a source for some fairly obscure sheet music, and somehow stumbled on scribd.com, which seems to have a vast collection of all kinds of published documents (not just music) which are apparently uploaded by registered users.
Lots of ads appear with the docs; I assume that's their revenue model. Anybody can look at stuff on line, but you have to register to print or download.

What I wonder: a lot of what I've looked at so far - again mostly music- must still be copyrighted. How can this be legal?

[powerplay]

There appears to have been some controversy and it looks like you have to pay to download most stuff from Scribd now.

Scribd - Wikipedia, the free encyclopedia

The last paragraph under Controversy -

[In August 2010, Scribd began beta testing premium services including the Scribd Archive. The test was met with minor community backlash leading Scribd to make changes to its policies[clarification needed]. Now when trying to download almost any document from Scribd, users are asked to pay for it first via their premium content service.]