After the election, every variable will be examined. What factor made a difference in such a tight election? The weather? Number of volunteers? Did blogging shape the race?
The Times thinks that bloggers did have an impact and has the opinions of some of the bigger names.
For the most part, bloggers seem to preach to the choir, and thus had little effect. Glenn Reynolds swayed no voters. The CBS/Powerline thing might have had some impact. The relatively few on-the-fence bloggers, like Dan Drezner and Andrew Sullivan, tend to have less rabid, partisan readers, and might have actually changed a few votes.
I think that the Times article on Bush’s doubt-less mindset based on his religious convictions was pivotal. I have heard that article mentioned several times by elites, while explaining their decision to vote for Kerry.
UPDATE: Brad deLong picked up my idea that the Suskind artlce on the peculiar Bush mentality was influential. Comments there. (Thanks, Brad!)