The medium really is the message here. It's not that bloggers are terribly gifted polemicists. Some are, most aren't. It's just that technology has reduced costs for the dissemination of information and opinion to zero. Which wouldn't be a big deal if the media (in all nations) were diverse. Then you'd just have further, amateurish opinions and news-hypers to choose from.
But because media institutions tend to be monolithically partisan (always tending to the left, though what the "left" is varies country by country), suddenly having a zero-cost-of-entry Shadow Media can actually make a difference.
Not because bloggers are saying things that no one else is, but for the exact opposite reason: because we're saying things that millions of other people are, only those people never get to register their voices in the establishment media. Or at least those opinions are given short shrift.
An elite can rule against the wishes of the majority of the popuation only so long as the majority of the population doesn't realize it's actually the majority.
So long as those who actually represent the true national consensus falsely believe they hold a minority or even "extremist" view -- a belief imposed on them by a monolithically partisan media -- they will not agitate for change nor express their true political wishes, for belief that such an effort would be futile.
And possibly "extremist."
An elite ruling against the wishes of a voting population is an inherently unsustainable situation. At some point --as with the Reagan Revolution of 1980 -- the house of cards must fall. But sometimes it may take quite a while indeed.
Zero-entry-cost media -- blogging -- doesn't allow that false belief to persist as long as it once could. Again, not because bloggers are saying what the public doesn't already know; but because we're saying what the public damn well knows, but just isn't really sure enough other people know too.
A zero-cost amateur blog in France helped fell a five-hundred page document that took millions of pounds/francs/marks and years to produce. Had easy and rapid connections between like-minded people not been possible, the "constitution" might have passed, simply for lack of public belief that they could actually successfully oppose it.