Booman the politico makes some recondite point that is also not easily understood by the lay person.
What brought people together into progressive blogging communities and networks was related to policy (the invasion of Iraq, torture, illegal surveillance, regressive taxation, bad environmental policy) but also other things (a one-sided corporate media, incompetent government, and lack of meaningful and effective resistance by the Democrats). But notice something. The progressive blogosphere rarely if ever engaged in serious policy debate about legislation pending in Congress. Insofar as it was discussed at all, it was normally opposed. And that kind of blogging can be habit-forming. What was appropriate when the Republicans ran everything is carried over and used against the Democrats.