At their best, comment threads can put topics in a new light, stir discussions, create community, even uncover new talent. Richard Lawson, now a senior writer at The Atlantic Wire, rose through the Gawker ranks from anonymous commenter to star writer. At The Atlantic, senior editor Ta-Nehisi Coates had a particularly incisive commenter who went by the handle Cynic. We thought his observations in the comments section were so good that we asked him to contribute to the site under his own name. Now Yoni Appelbaum, a doctoral candidate at Brandeis, writes for us on everything from the Civil War to presidential politics to Amtrak.

Of course, commenters frequently are not at their best. Too often, comment sections are cesspools of vitriol, magnets for haters and trolls and spammers. Threads get hijacked so they are only tangentially connected to the topic of the underlying post. The lack of friction -- mere seconds elapse between furious keystroking and posting to the world -- can privilege snark over enlightenment.

The main issue here is whether comments create such a negative environment that they detract from the reading experience, a proposition to which many would answer yes. But some researchers fear the problem is deeper than that. A study by professors at the University of Wisconsin-Madison found that people who read a neutral article about nanotechnology followed by uncivil comments were more likely to perceive risks with the technology than people who read the exact same article with civil comments appended. The alarming implication here is that the comments affect how readers understand the journalism.

So what's a publisher supposed to do in the standoff between the world of good and bad comments? Some are, understandably, giving up. The ABC affiliate in Washington, D.C., became so exasperated by the "mean-spirited, and at times hateful comments" that last month it pulled the plug. "These comments provide no value to our readers and are time-consuming to moderate," wrote the station's director of new media.

There's the rub. It takes a lot of moderating time to foster a positive commenting section. Writers or editors have to jump into the conversation to keep it on track, or to mete out justice by removing comments or even banning the worst offenders. It's nice to think we'll just let a thousand flowers bloom; in reality the garden needs to be weeded. But who's got the resources? Coates says that at one point he was spending as much time moderating his comments section as he was writing posts for the site. That's untenable -- though, it must be said, Coates's hard work created a terrific environment for readers and for himself. (When Ta-Nehisi won a National Magazine Award earlier this year for his magazine essay, Fear of a Black President, he thanked his commenters for the good suggestions they had made as he reported and wrote the piece.)