Anywhere But Blogs
The primary "are you with us or against us" line has been drawn on the morality of war in the current era, and a lot of blogs have fallen to the right side of that line. Many of those who chose to defend the "only moral choice is peace" have been pushed further and further into indefensible positions as evidence of genocidal fascism mounts. Since one of the key elements of the blogsphere is feedback, the viability of maintaining a forum on an indefensible position is limited.
"Anybody But Bush" may look great on a bumper sticker in traffic, but having to argue that you would prefer the leadership of the free world in the hands of the Gambino crime family in the comments section of your blog is somewhat less rewarding an activity. Now when I saw that bumper sticker in traffic last week, I was only able to prevent the person from cutting in front of me. On a blog, I could have destroyed that person's worldview in a few terse paragraphs.
One of the critical problems for the leadership of the left is that they have chosen to a political identity that can be defended in the tight space of a bumper sticker slogan or the clamor of a protest rally chant and not elsewhere. The ability of your accusers to hyperlink to reams of contradictory evidence and commentary is not faced in rush hour traffic or the packed confines of an angry mob. The quantity and quality of the methamphetamines you are taking diminishes precipitously over time, and if you post something particularly stupid it sticks around on the Internet much worse than bumper sticker glue.