We are living in an age of rage. People are angry with government, with media, with religion, with migration, with Europe, with big business. That frustration comes burning through in comments posted below stories on our website, a facility offered in the spirit of open journalism that has seen an extraordinary growth in numbers, sometimes running as high as 65,000 posts a day. That’s a huge number – and it’s producing its own frustrations, not least among those who feel they have an inalienable right to comment.

This outburst arrived in my inbox recently: “Re the excellent article by Jeremy Corbyn. You stop the comments at a mere eight. What on earth do you think you’re playing at?” The tone was typical of this new age. In reply, I explained what the paper was “playing at”: trying to curate a reasoned debate in comments, not shut down discussion. That sometimes meant closing them for a while and then reopening them when we had a sufficient number of moderators to handle the volume. I noted that the total at the time of my reply had grown to 2,058; our reader had spluttered too soon.

But more concerning is the ever-rising level of abuse, trolling and “astroturfing” (propaganda posting – an artificial version of a grassroots campaign) currently polluting what are often illuminating and stimulating discussions.

In response to this menace, some news sites, including Reuters, CNN and the Chicago Sun-Times, have abandoned comments altogether or heavily restricted them; others, such as the New York Times, pre-moderate every post. That’s not going to happen here, but things are about to change.

I asked Observer journalists for their experience of comment threads. Most reported being abused. Kate Kellaway told me: “The worst of the comments remind me of road rage – just as drivers feel protected by their cars, so people feel protected by their computers – and behave in ways they wouldn’t dream of behaving if they were introduced to you face to face.”

Others reported positive interaction, with “nuggets of gold” to be found below the line. “Of course, we want a dialogue with our readers, but if only it could be conducted in a tone of voice that’s reasonable,” said Robert McCrum. “I’ve found that once things get out of hand in a thread it is virtually impossible to dial it down. I’ve got used to it. I don’t like it, but as a champion of free speech I’d rather let it rage on than try to curb it. But I do say that anonymity is bad for everyone.”

Others echoed that thought on anonymity but it’s too late to demand disclosure by commenters; anyone determined to stay anonymous can create an infinite number of online aliases.

Certain subjects – race, immigration and Islam in particular – attract an unacceptable level of toxic commentary, believes Mary Hamilton, our executive editor, audience. “The overwhelming majority of these comments tend towards racism, abuse of vulnerable subjects, author abuse and trolling, and the resulting conversations below the line bring very little value but cause consternation and concern among both our readers and our journalists,” she said last week.

As a result, it had been decided that comments would not be opened on pieces on those three topics unless the moderators knew they had the capacity to support the conversation and that they believed a positive debate was possible.

The policy would be worldwide, applying to our UK, US and Australia offices, as the issues were global. And, where they were open, it was likely that threads would close sooner than the typical three-day window. “We want to host conversations where there is a constructive debate, where our audience can help us broaden our journalism with their expertise, their knowledge, their considered thoughts and opinions, and where they can use our site as a platform to make connections with the world and with those around them,” added Hamilton.

This was not a retreat from commenting as a whole, she said; it was an acknowledgement, however, that some conversations had become toxic at an international level – “a change in mainstream public opinion and language that we do not wish to see reflected or supported on the site”.

It’s a move that I’m sure will be welcomed, not only by journalists but by the many thousands of readers who already contribute constructively to positive debates, offering personal experience, considered opinion and, of course, constructive criticism of our journalism.

observer.readers@observer.co.uk