if you're on a mac, you can right click on a selection of a single or multiple *.wav files, click "Services" > "Encode Selected Audio Files", set the "Encoder" to "iTunes Plus" and then click "Continue". after some time, this results in a *.m4a file, which for example made a ~625mb file go to...
i also found them through soundcloud. i was looking for covers by some of my favorite voice actors and a track of one of the volumes of the kare pillow series came up
i do this with a lot of different things! it's a really bad habit. like others have kind of said, i think part of it comes of that the internet is not really forever, and things can get lost so easily when links die. it is super fun though when i finally open something i downloaded a while ago...