If you feel strongly about a particular issue, there is some really smart person out there who has written a book explaining why you are right. If your friend disagrees with you and you can't win the argument you can be sure that the author of the book would kick her sorry ass in a debate. This helps us believe that our beliefs are intellectually respectable. Once we have discovered the experts that support our views we can think up reasons why these people are reliable and well intentioned while the "experts" who disagree with us have ulterior motives for saying what they do.
The tendency to give more weight to people who agree with our views and dismiss arguments or evidence from the other side is called confirmation bias. Julian Baggini has a good article on it here. The problem with confirmation bias is that we all suffer from it and I think its especially problematic in blogging because most blogs focus on their on little pet issues and are read by like minded people. I think it's quite interesting to see how confirmation bias acts when someone has legions of followers on some particular topic but then differs with the consensus view among those fans on some other topic; how should those fans react? I think the instinctive response is to say something like, "He's a smart guy but everybody makes mistakes" or find some other motive for why he has that view. For example; most libertarians love Robert Nozick and they usually love killing and eating animals. But Nozick argues that using animals for our pleasure is not justified in his libertarian masterpiece Anarchy, State and Utopia. In my experience libertarians are not bothered by this fact and don't hesitate to dismiss his argument. Of course, Nozick's attitude towards animals just made me more confident that he's right on other things.
So if it's true that people are mainly interested in justifying beliefs they already have what does that say about our attitude towards truth?