Mixed bag.
There are some intelligent and articulate bloggers of the both the left and right, and there are some first class hammerheads of both ilks who happen to write reasonably well, and there are more than a few insidious and invidious types who have discovered that the internet is an ideal forum for misinformation and disinformation.
There is a significant number of voters who regard the internet and blogs as a "superior" source of opinion and information, and are particularly susceptible to internet demagogues.