Well, it's rare to find one. Usually there's always a handful of people who ruin the comments section because they just love to start trouble with others. Youtube perhaps being the absolute worst, filled with hate and ignorance.

But there are safe havens around. One of which is Robert Ebert's blog:
http://blogs.suntimes.com/ebert/

He's a good writer, and he seems to have built up a level-headed community of people that follow him.