I used to run another blogspot that was specifically for sharing experimental, rare, or out of print music. It's no longer operating, but all the links still work. If you're interested in this kind of thing and you'd like to thumb through it, go here:
To brag a little, the site was pretty successful, with tens of thousands of downloads (not albums, but actual downloads) towards the end. I didn't think it would have turned out to be anything, but it did. Then again, my writing style sucked back then, and a lot of the reviews come off as really amateurish. It's kinda sloppy at times. But, uh, ignore all that.
If you're aware of what the NWW List is, or Vanity Records, or Trans Museq, you'll wanna check it out. There are also a few cool other gems here and there; fluxus sound works, Dada and Futurist recordings (Luigi Russolo and Marcel Duchamp), etc.
Now, the absolute KING of experimental blog-sharing is:
who inspired me to make my own, as well as opening me and others up to hundreds of great albums. Seriously, this guy (now a trio) has put up a couple thousand albums. Go look through it, it's worth it.
A few other favorites:
http://eatmyartout.blogspot.com/ (no more updates?)