Every community has its hot-button issues and sacred cows -- and often these are exactly the topics that community news/info sites should address. The catch is, if your site allows comments, the comment threads attached to such content often gets derailed into flame wars or off-topic meanderings.

In a recent post, Scientific American blog editor Bora Zivkovic offered some sound advice for how sites can improve the quality of reader comments -- as well as some striking research demonstrating why you should undertake this effort, if you hope for your site to play a constructive and influential role in your community.

First of all: Do website or blog comments still matter? Hasn't all community discussion moved to social media? Is it worth the effort to encourage high-quality comments on your site?

That depends on the preferences of your community, the goals of your site, and the topics you cover. When it comes to engagement, allowing comments on your site can be a powerful demonstration that you care what people in your community have to say. On-site comments need not be your sole or primary engagement channel, and it's probably not helpful to have a goal of maximizing comment quantity (rather than quality).

However, comments will be an effective engagement tool only if people clearly see that you really are listening and do care about (and respect) their views.

Zikovic wrote: "Why are so many comment threads so nasty? Because they are not moderated! At all! In ALL sense! If commenters think your commenting thread is a public space where they can do whatever they want because nobody's watching, they will do whatever they want. And that is not pretty. And then the potentially constructive comments never get posted, because normal people do not want to waste their time thinking and writing comments that will just get flamed.

"If you don't delete or 'disemvowel' inappropriate comments, people will think you are not even reading the comment threads. If you don't show up in person, nobody will know you are even interested in their thoughts. If you don't delete [or ban] the trolls, the trolls will take over and the nice people will go somewhere else."

Sounds like common sense, but this means that curating comment threads needs to be someone's job. Preferably the responsibility of everyone who works on your site, at least to some extent.

That may sound like a lot of work -- and for a highly prominent site like Scientific American it probably would be. But for most community (especially local) sites, the comment volume is likely to be lower and focused mostly on a few topics. You can target your comment-curating efforts to yield high-impact results on the most important issues.

Much of this can be managed through comment moderation schemes. Zikovic described several in his post -- from automated comment spam filters, to approving individual comments (and killing obvious off-topic or trolling comments immediately), to editing comments (such as deleting links from sites you don't want to send traffic to).

But in addition, he cites active participation by the site's operators as the key to generating quality discussion in comments.

How to choose which comments to delete or edit? "It is not about blocking every opinion that is different from mine," wrote Zikovic. Referring to one of the many posts about climate change on his blog, he observed: "Obviously, some of the commenters disagreed with me on the content and conclusions of my post. And there are a couple of comments there by obvious climate deniers that I left standing because they were on-topic and civil in tone, despite me not agreeing with them one bit. It is not about censorship, it is about tending the garden of one's commenting threads, by nurturing the good flowers and removing the weeds."

What makes this worth the effort? Zikovic cited a recent Science magazine article (subscribers only) which described some research into online science communication, about how the tone of comments on an article affected how other readers perceived and responded to an article.

"An article about nanotechnology, a topic most people know very little about and usually have no a priori biases for or against, was presented to the test subjects. Half the people saw the article with (invented) polite, civil and constructive comments. The other half was given the same article but with uncivil comments -- essentially a flame-war in the fake commenting thread. The result is that readers of the second version quickly developed affinity for one side of the argument and strongly took that side, which affected the way they understood and trusted the original article (text of which was unaltered). The nasty comment thread polarized the opinion of readers, leading them to misunderstand the original article.

"They specifically chose a topic about which most people know very little and do not already have any opinion. Neither the article nor the comments contain sufficient information to turn the readers into experts on the subject. So they have to use mental heuristics -- shortcuts -- to decide what to think about this new subject. Uncivil, aggressive comments resulted in quick polarization. Readers, although still not well informed about the topic, quickly adopted strong opinions about it."

In a nutshell, that is the high cost of leaving comment threads untended and unresponded to. A hands-off approach to comments can easily undermine your engagement goals by discouraging constructive participation.

Offering comments is not mandatory. You can elect to offer your communities other ways to interact with you -- including via social media, e-mail, or "letters to the editors" submissions.

But for most community sites, a better approach is probably to conduct regular crowdsourcing projects -- where you solicit, gather, summarize, and present a range of views on a topic of community importance. Here the focus is on curation, and the goal is to use the best comments to form a uniquely compelling form of content. Crowdsourcing projects can be small scale (such as asking open questions) or more ambitious (such as trying to gather particular types of stories or examples from your community, which typically takes more active rather than passive work).

Of course, a community site that does not allow direct comments is an easy target for criticisms that it's not really interested in discussion. An individual blogger, such as Dan Conover probably can successfully turn off comments without tanking his credibility. But a community-focused, mission driven, engagement-oriented site probably doesn't have that kind of leeway.

So it's probably best for community sites to allows comments, at least on some types of content. Maybe not all, depending on the resources of your site and the level of controversy of the topics you cover. But you can experiment with how you offer and engage in comments.

Set some quality-focused benchmarks for comments on your site. These might include:

• Internally produced ratings for the best-quality comments
• Identifying and recognizing your most constructive commenters. What makes them constructive? Do they offer valuable insight, raise especially good questions, help answer others' questions, or offer suggestions?
• How many troll/off-topic comments do you have to kill, and what's your ratio of low-quality to high-quality comments? How is that trending over time?
• How often are you able to springboard from comments to new content on your site?
• How often do people discuss your site's comments (not just the original content you post) one social media or other blogs, forums, or sites?

These kinds of benchmarks and metrics can help you gauge the value of engagement through comments, thus demonstrating whether your efforts to foster and curate discussion are really paying off.