The phenomenal success of left-leaning blogs, including TPM, Daily Kos, and the Huffington Post, is no doubt attributable in large part to the dissatisfaction and passion felt by Democrats surrounding the Bush presidency. The challenge for these sites is going to be to keep the passion and interest up during an Obama presidency. It will be interesting to watch.
I expect that the right side of the blogosphere will grow during the Obama presidency, becoming an especially potent force in shaping who the Republicans will choose in 2012.
It is very interesting how the partisan press has been revived thanks to the Internet. But it works best alongside non-partisan press, as both keep the other honest.