We call it "try before you buy." It's the shareware model applied to music. Listen to 373 complete MP3 albums we've picked (not 30 second snippets).
We let the music sell itself, because we think that's the best way to get you excited by it.
And here is what Mark had to say about it from the blog post:
The concept of an open pricing model such as this is intriguing and brings up several thoughts that are worth discussing further. For instance, there is a good deal of talk these days about the shifting paradigm of marketing techniques. Blog publishers are growing more irritated with the notion of corporate hype and the open source movement seems to be taking root in the mainstream.
Either corporations will soon learn that consumers are tired of having their options limited and some aspects of their lives dictated by companies, or else all this Web2.0 stuff is just hype and will soon blow over.