When you publish a diary here, something remarkable happens. It emerges into a world of folks who now have the opportunity to read it, think about it, comment on it, share it with others, and add you to their "stream": following you to ensure that they won't miss any of your future writing.
There's a name for people like this: customers.
Sure, you could just write your brilliant and insightful diary and save it on your hard drive where it would languish in obscurity. Instead, you publish it here with hopes that it will make a difference in the world, or at least in "someone's" world.
Once your diary is out there, commenters can share their reactions. They may agree or disagree with your premise. They may praise your writing. They may offer examples that support or refute your conclusions. They may ask questions. They may react to the comments of others. They may just stop in to say hello.
Your job as the diarist is to serve as the host or hostess, making your commenters feel welcome, interacting with them respectfully and graciously. You may not always agree with them. That's fine. Just keep in mind: you can disagree without being disagreeable.
By stimulating discussion, some amazing things can happen. You may find that your commenters bring a fresh perspective, and that they build upon and amplify your points. Even if you agree to disagree, you can earn the respect of commenters who will look forward to further discussion in subsequent diaries (yours or theirs).
Why does this matter? Read on below the aura of respectability for more...
Think of your diary as a newly published book, and the comment thread as a book signing "meet and greet". While your book may be the best thing ever to hit the printed page (or the Kindle, Nook, or iPad), your interactions with buyers and potential buyers can sell a lot more copies.
Alternatively, if your interactions with these folks come across as rude or dismissive or argumentative, it may alienate the very people who could be your best customers (or ambassadors).
It doesn't take much. A snide reply that questions a commenter's viewpoint, credentials, background, or character. While some people might see that as a cue to ramp up the rhetoric and fire back, others will disengage and make a mental note to steer clear of you in the future.
Neither outcome will help you here. If you start - or encourage - arguments in your comment thread, it can become a sideshow, distracting from what might have been a well crafted and important diary. While a sideshow may be an entertaining spectacle, it's probably not a winning strategy for advancing your reputation.
Comment threads are also taken into account when the "Rescue Rangers" read your diary for consideration for "Community Spotlight". Many otherwise good diaries - well written, informative, thought-provoking, and compelling - drop from consideration if the diarist's interaction with commenters foreshadow (or confirm) a "pie fight".
The intent of Community Spotlight is to provide greater visibility for deserving diaries and diarists. Engaging in counterproductive behavior in the comment thread will kill your chances for rescue (as will "posting and running", where the diarist doesn't interact at all with commenters).
Bad behavior by others in the comment thread is a test of your diplomatic skills as a diarist. If a commenter takes issue with your diary, try to respond without escalating the matter. They may simply have misconstrued what you said. Don't assume that they have a bone to pick with you. Ask them a clarifying question. See if there's some common ground.
Let your other commenters weigh in too. Chances are if someone has really said something egregious, another commenter will call them on it. Sometimes it's advisable to let those people deal with any bad behavior so you can focus on the constructive comments.
The point isn't to avoid controversy; it's to manage it constructively. I've learned a lot from my commenters. It's no wonder: they're among the most intelligent, literate, well-informed, witty, and good-looking people on DailyKos. They're ready to comment on your diaries too.