Popular Science disabled its commenting system last week, and the New York Times has a nice discussion on the positive and negative aspects of comments.
Even on sites where comments are actively screened — like Nytimes.com, where moderators either post or reject submissions — people who think evolution is bunk are generally permitted to voice their view, often to be shouted down by others; for some readers, following such comment threads is part of the fun. But Popular Science and other publications do not have the resources to moderate all comments, so personal attacks and other bits of ugliness can slip in.
Comments are tricky. I don't have comments on any of my new sites, primarily because most of my sites are too new. Right now, all I get is spammers. A spammer is a step below a nasty, ugly troll when it comes to comments. At least the troll is, hopefully, on topic.
Even when my sites pick up (notice I say "when", ever the optimist), I may not have comments. While commentary in the New York Times is usually worth reading, I don't really notice a dialog happening. To me, the good part of comments is that they start a dialog. You can read thoughtful alternative views in the Times comments, but you don't see people engage each other in a fascinating, interconnected exchange that makes you want to jump in and be a part.
You do see discussions at something like the Huffington Post, but my lordie, they're generally awful. The same with comments to stories at most local newspaper web sites—full of ugly people with really bad language skills, determined to have the last word. All full of CAPS and exclamation points!!!
HERE ME!! I'm WRITE!!!!
LOL!!!
I used to see exceptionally good dialog at one of my favorite web sites, Food Safety News. Insiders throughout the food industry would stop by and engage in long thoughtful discussions—civil and intelligent, even when the folks didn't agree. Something happened, though. I'm not seeing the participation I used to see. Oh, there's comments, but they're slowly sliding to the "anonymous troll with bad language skills" side of the comment quality scale.
I'm actually a little concerned that it was people like me—outsiders who are interested but don't have extensive backgrounds—who may have chased the professionals away. Is this another issue about comments? Too many people with varying backgrounds become so much clutter when all grouped into one space?
Of course, some topics generate hundreds of comments regardless of where the story is posted, but the dialog they inspire is less than edifying. Don't take my word for it: write a story about horse slaughter and opening up the horse meat industry in the US, and you'll see what I mean.