Here's something you want to see, something that exemplifies this process. It's a collage of cover versions of Paranoid Android by Radiohead.
But that misses the point. Firstly, this is the point of the Internet: how wonderful that anyone can share their passion, their musicality, their personality in this way? How brilliant that their efforts could be combined so cleverly into a new and different and, arguably, wonderful version that includes contributions from so many people? How touching that people who will never know each other can collaborate on a larger project?
Secondly (and I can't stress enough how much you should click on this link), everything is a remix.