I started out writing a response to this thread on weblogging as journalism at kottke.org, but I ended up with yet another articulation of my thoughts on technology and the possibility of positive social change. So here it is for posterity... and your reading pleasure, I guess.
The most useful way I've found of looking at blogs qua social change (not "revolution") is as a network of folks connected directly. This creates the potential for people to bypass the ideologically twisted mainstream media and spread accurate sources among themselves. I say potential because there's no guarantee that anyone will actually do this. When I look at weblogs in general, I mostly see a large range of opinion, all happening within mainstream ideology (which most people see as common sense). That's distinctly un-revolutionary, as I see it.
To really get to the bottom of an issue or event takes a lot of tedious research, systematic questioning, and hard work. Note that after that's done, one still has to communicate it in a way that people will understand its significance, which is even harder than doing the research in the first place.
That's just, like, my opinion though.
First, when I say weblogs... I include MetaFilter, Plastic, Slashdot, and collaborative media sites like Kuro5hin.
At this point, I kind of worry that the term "weblog" has lost its usefulness and even its meaning, since it seems to mean "updated web site that has original content and links to other web pages." We might as well be talking about "self-published web sites", which is fine, but why do we need to stretch the term farther than it can go?
I think there's a lot of potential in collaborative work on the net, though again, I think if its going to cause any real (i.e. meaningful) changes, it has to happen on the basis of a different understanding of how meaning is produced. That said, I've spent a bit of time thinking about different ways of collaborating online, which folks may or may not find interesting.
A lot of my skepticism comes from the fact that almost every new communications technology (radio, TV, newspaper) was initially seen as amazingly liberating and revolutionary, but was ultimately coopted by commercial interests.
In Rich Media, Poor Democracy, Robert McChesney has an intelligent chapter about why the internet isn't as revolutionary (at least, not inherently) as folks like to think. Here's an article by McChesney discussing much the same theme.
An interesting way to approach the problem would be to try to understand how old media could be better used in new and different ways to undermine the monopolistic grip of the big 6 in favour of a more grassroots approach. In terms of overall cost, radio and print are unquestionably cheaper than the internet. They're also more widely accessible to folks in lower income brackets, and of course don't require a computer screen. :> Most people I know are much more likely to listen to a radio show or read a newsletter than to look at a web page.
The remaining advantage of the internet, then, is the fact that it isn't constrained by geography, and the fact that it is searchable. This begs the question: how might the internet and other media be combined to create something simultaneously more powerful, more versatile, and more accessible.