Bias in the blogosphere?

In this essay on the political leanings of bloggers, Robert Corr says “I’ve attempted to apply the Herman/Chomsky propaganda model to the blogosphere, and submitted the essay for my Politics and the Media class.”
I’m still reading it, but he makes some good points about the economics of cyberspace and the climate of the blogosphere.
It seems to me, though, that many tech bloggers lean left (or libertarian) just as many post 9/11 instabloggers lean right (or libertarian). It’s just that the tech bloggers are less engaged politically, at least in the sense that they have other things to blog about than Robert Fisk’s latest anti-Bush screed.
He makes the point (among others) that bloggers are mainly commenting on pre-filtered news (and talking points):

As Andrew Orlanski pointed out, “If I was in a position of power, I’d be delighted to see news reporters supplanted by blogs, because blogs — for all their empowerment rhetoric — are far easier to divert and confuse than a few persistent and skilful reporters.”

He also makes an interesting analysis of the link “economy” among bloggers as a form of advertising. Then again, he quotes the New Statesmen on the relative influence of Glenn Reynolds and Andrew Sullivan in the blogosphere in which InstaPundit is said to have “only 40,000 readers a day.”
I suppose a newspaper would see that figure as paltry and unsustainable from the advertising-pages perspective, but since when is 40,000 people a small number? If you sell that many books you can make half a year’s pay. Newspapers may serve 10 or 100 times as many people but they are not written by just one person alone! (End of digression.)
At Corr’s own blog, MentalSpace, he hosts a Political Blog Map plotting bloggers on the 2-D cartesian grid, based on the Political Compass quiz.
The sample of bloggers shown is small, but it begins to bear out my sense that the slant online is toward libertarianism and away from authoritarianism, more than a left/right divide. Then again, we need other dimensions, because where does communitarianism come in?
Full disclosure: RFB (or, in my political guise, Bite Media) scored -2.62 on the economic left/right axis (minus is left, plus is right) and -6.26 on the authoritarian/libertarian axis (minus is liberty, plus is authority).