In January 2013, the Guardian had an article on the statistics of online commenting, showing that most readers don't comment, and those who do comment have an online footprint (and thus influence) out of proportion to their actual numbers.
In 2013 and 2014, as online discussions of abusive commenters increased, more posts showed up on commenting--whether to quit allowing comments, whether comments should be moderated and if so, how to do it, appealing to trolls and other abusive commenters to shape up (which had the predictable effect of having them spew even more venom), and so on. Spam (which is also a problem in comment streams) was mentioned less often and attack comments were mentioned more often. More blogs closed down comments. More blog owners began to end, or more stringently moderate, comment sections.
Barry Ritholz, for instance, in February 2013, wrote a post about problems with comments, titled as if he was considering ending all commenting, but then stating his intent to separate the goats from the sheep and refuse to publish those comments he felt were abusive: selective comment control.
Selective comment control requires moderation--which doesn't work well with automated systems (as shown by the attempts of large social media sites to police by algorithm and their insistence that their key words prevent abuse...the evidence is that no, the rape threats still get through.) Moderation also takes time and effort and the moderator is exposed to the venom even if not the target of it. Independent blog owners end up spending time checking through comments that would be better spent doing something else (research, writing another post, doing the housework and laundry, etc.) Many independent blog owners do moderate comments (Scalzi, for instance) and (like him) post advice to commenters, hoping to teach people how to be better commenters. In some venues this works, if the blog owner is willing to spend the time reading every comment, strictly enforced his/her own guidelines, and occasionally posts reminders that the guidelines are there and transgressors will be deleted before they appear.
Katherine Aragon, on her advice blog for bloggers, posted recently on whether you should close comments on your blog, offering examples of others who had (or hadn't) done so. She links to other examples of blogs that no longer accept comments, and their reasons for making the change. Among other things, she points out that though allowing comments may drive traffic to your blog, increased traffic can be used by "loud" commenters to drive more traffic to their blogs. Self-promoting comments, with links to the commenter's site, are a problem on some business sites where the commenters may be competitors. You don't find a flashing Ford ad hanging over a Toyota dealership.
And not all blogs need (nor their owners want) huge amounts of traffic anyway. A small town librarian's blog on what books are new at that library and how the bake sale did is intended for the amusement/education of people who use that library--not the whole world. (It's also unlikely to garner a lot of hate commenters if the librarian never mentions race, sex, or environmental issues.) Blogs that are intended to build a brand or platform, on the other hand, are intended to draw increasing traffic over time, and the early advice to such bloggers was to have a comments section and engage with all the commenters. Lively discussion, it was said, drew more people to the blog than the contents of the blog itself.
From my first online presence, in my SFF.net newsgroup, I've moderated fairly firmly to keep the "tone" where I liked it. It's my space; I pay for it with my own money, so I perceive it as "my" space, not a public square. Anyone's welcome to read there, but no one is entitled to transgress the house rules. It's a virtual "fishing cabin on a rock-bottomed river" where friends can drop by and relax and discussions stay polite. When I added this platform some years later, I had pretty much the same attitude (I pay for it; it's my space) but loosened the "good behavior" somewhat, with mixed results. First off, minus the much better spam control at SFF.net, I had to watch out for straight-up spam arriving in batches, and attaching to older posts without any notice to me. Posts advertising knock-off shoes, purses, watches, etc, etc, are a time-wasting nuisance. Second, LJ was better known and more widely accessible, so more trolls and more hornet swarms (people who follow trolls and flood a venue with angry, abusive comments) found me. Moderation was necessary (is necessary) and trying to make a place for well-written, rational, polite comments on all sides of a question, while pruning off the abusive, irrational, threatening, foaming-at-the-mouth ones took time (lots of time, in some cases.) My experience has been that many people prefer to read and comment in an environment that is not too loud and not at all abusive, where they can feel heard, if not agreed with, and not fear the attacks of trolls and hornets. (There are always some who don't want any moderation and insist they're happy in the midst of angry chaos. Tough luck.)
My other blogs all have a comments guideline section and it's enforced firmly but not always rigidly. The most active of those blogs has a reasonably active commenting community that nearly always stays on topic and behaves well to one another (I see all new commenters in moderation and have sometimes contacted one in email to point out that a comment isn't acceptable but they're welcome to try again. Only one of those has calmed down and joined the group. If it's really nasty, I just trash it without responding.) This venue, LiveJournal, remains the odd one out. SFF.net isn't an infinitely large group, and I enjoy being there--I have friends whose newsgroups I read, and I sometimes get into the open discussion groups. People there know what I will and won't tolerate, and it's a rare thing anymore that I have to issue a Buzz Off notice. But LJ is well in the radar scan of generalist trolls and hornet swarms, so saying anything at all controversial (and I do, and will again, in amidst the posts on knitting socks, making soup and other cooking neepery, and innocuous posts on writing) is likely to bring down the proverbial shitstorm. And though I enjoy comments on my other posts, it still takes time to engage with every commenter--time I often do not have.
So far, what I've tried is disabling comments for posts likely to have this problem. I'm not ready to disable comments altogether, here or elsewhere. But as life goes on and time grows shorter (staring at he next birthday with the big 70 on its face does make one think of how one wishes to spend remaining time) answering every comment, and plowing through spam and trollspew to separate the good stuff from the slush is less appealing. I have friends with serious problems I should be helping and comforting (this one has cancer, that one was widowed, that other one was fired unjustly...) and though I'm glad to know someone's reading the online stuff...I cnanot possibly fulfill everyone's desires. So if you find comments disabled on a given post, it's because I figured it would be too high-traffic for me to deal with in the time (and energy budget) I have. I wish LJ had a way to disable comments when a post is a given # of days old (because dealing with packs of spam that arrive to clutter much older posts is a real PITA, and because sometimes everything worthwhile is said within the first 5 days.)
It's not a swipe at anyone here. It's practical--there's just one of me, and I have urgent stuff to do that is not involved with blog comments.