Everyone's saying it. Just for instance, Dave Morris in the ever-bright Eye:

Back here in North America, mixtapes are like, so hot right now. For bringing them to the attention of the hipsterati, you can thank Sasha Frere-Jones [blog] at The New Yorker [here's the link], the Pitchfork singles column and DJ Nick "Catchdubs" Barat, the latter of whom has lately played No. 1 spinna to everyone from M.I.A. to A-Trak. Whether or not you think glossies like The Fader (where Barat is also an editor) ought to be criticized for acting like they invented hip-hop culture, you may still take a step back upon seeing the title of Barat's Saul Williams (pictured [see link]) mixtape, called Real Niggery Vol. 1.... More.

How to make hip-hop: sift two parts creativity, one part boredom and add a wealth of cheap, outmoded technology. Stir, bake for a couple of decades at high heat, and voila -- bona fide street culture. Judging from their blank cassette museum (see Totally Wired, May 19, 2005) and now DJ Artyom, pioneer of the cassette turntable, dare we suggest that Russia is going to be the site of the next happening music scene? Artyom's set-up looks basic, but his mixing gets better as his Love Sex Music tape progresses. We don't know what a Russian "Rapper's Delight" would sound like, but it's only a matter of time before we find out. (www.soundresearch.narod.ru/engcassettedj.htm)

[From Artyom's site: "You can download and listen to samples from this tape. I apologize for curvature in the first mix - it because Donna Summer strongly groaned :-)."]