Sometimes you read a post in the comments below an article that stops you in your tracks. “I feel that I’m taking a risk by what I’m going to write today,” it began. “A number of years ago I had severe mental health difficulties. At its worst I was having about 10-15 panic attacks a day ... Everything has been good for a long time, with the occasional blip. However, about two months ago the severe anxiety began to reappear ... I have one request. Please don’t tread carefully around me because of what you’ve just read.”

The comment was written by Breezehillpete, a regular contributor to the comments below the Guardian’s Running Blog, and a source of encouragement and humour to other readers. But now he needed help himself. Very quickly they gave him sympathy and advice; there was a huge outpouring of affection, alongside acknowledgement of how difficult it must have been to write that post.

And that is what the Guardian’s Running Blog is all about.

Four years ago, I launched the blog as a supportive corner of theguardian.com for runners; a place to learn, chat, be inspired and discover thought-provoking articles. The aim has always been to include readers of all ages, speeds and levels of motivation – whether your target is to run a marathon in under two and a hour hours, or simply to jog a few steps.

We publish two or three articles a week on subjects that have included blood testing for amateur athletes, weight loss and running as therapy. Then we’ve had some truly contentious subjects – such as whether men should ever wear running tights, and whether music is a lifesaver or unforgivable aberration when running. But the anchor of the blog has always been the Monday morning debrief.

The debrief, which I usually write, is a simple race report or a few paragraphs offering some kind of theme for the week’s discussion – but the main point is always the conversation below the line, in which readers share their running experiences from the weekend.

When we began publishing these Monday discussions in February 2013, not every reader thought it was a great idea. As one put it: “I can’t see this working. I don’t see why anyone would be in the slightest bit interested in reading about someone else’s run.” Thousands and thousands of comments later, it’s clear not everyone shares that opinion.

Many of those commenting are regular participants – from HilarySutcliffe who took up running in her 50s and claims to represent the “slow end” of the field (though she does herself a disservice), to Asta, who makes us all laugh with his tales of resolutely/insanely ignoring injuries that really ought to be rested. Race reports or comments come in every week from Australia, Japan, Poland and Sweden to name but a few – and if a regular commenter doesn’t check in, a virtual search party will try to track them down.

Why does it work? I think it’s because while some people might have friends, family or colleagues interested in hearing about the minutiae of their running adventures, many don’t – and even those with the most committed supporters can find themselves facing blank expressions or eye rolls upon excitedly announcing: “I got a personal best!” So, the blog provides a space where people can talk about the good and the bad of their running with others going through the same thing, swap tips on treating injuries, or just talk about their favourite shoes.

The atmosphere is warm and non-competitive, and the community always celebrates individual achievements – whether it’s a tentative reader making their first foray into commenting, or a speedster reporting on an incredibly fast race time. My hope is that new readers find the Running Blog a source of support. If someone has a question, I always try to help out – but most of the time another commenter has got there first. It is how an online community should be. That support also works both ways. The Running Blog was born less than a year after my own running journey began with the Couch to 5k app. Since then I have improved quite a lot; in April, I was hoping to run under three hours at the London marathon.

Alas, I failed to achieve my goal because I injured my quad after 15 miles, as I explained when writing, despondently, about the experience for the blog. The community’s response absolutely floored me. I spent much of the day holding back tears, as I read each comment and felt all the support usually swapped between commenters, directed at me.

It was simultaneously one of the worst – I was gutted, and in pain – and most wonderful days I’ve ever had. Later on Twitter, I saw someone (@holleyalex) write: “The Guardian’s ‘How was your weekend running’ truly has the most beautiful comments on the internet.”

These days, not only have many of the blog’s readers got to know each other virtually, some also quite frequently meet up in “real life” too, all around the world – I’ve met quite a few commenters at social post-race beers. The blog has become a sort of virtual club, complete with its own tongue-in-cheek motto: “Run faster!”

If we had another, more serious, motto, it would come courtesy of another commenter, mountainrunnermum. A few years ago, she wrote: “Running is the rope that pulls us forward.” It’s a phrase that has resonated with everyone, from those just wanting to nail the perfect Parkrun to those battling mental health issues. It crops up again and again.

The week after BreezehillPete wrote about his struggles, he was back in the comment thread. “I’ve loved this blog and the people on it for a long time, and my real-life family have known about its significance for just as long. So, thank you. Thank you for your interest and support and mickey-taking over the last few years. I wish that I could respond to you all individually, but it would be like the Oscars, the music would start playing and they’d drag me off!”

Kate Carter is the editor of theguardian.com/runningblog