I won’t reblog the already very-much-reblogged post about muxtape (awesome service, by the way), however, I’d like to point out this:
Tumblr is a damn good marketing platform.
I’ll second that, and add that Twitter definitely pushed it along, too (jnm tweeted at 9:57 this morning, now several hundred people have followed suit). It’s the marketing power of something really cool hitting the follow effect—via Tumblr or Twitter your “holy crap this is cool!” is picked up by people to whom you wouldn’t have emailed or IMed a link. Repeat a few hundred times, and there you go…totally fascinating.
And again: muxtape is astonishingly great.