This Concord man has been SFGATE's top commenter for years. So we talked to him.

John Geraghty reads SFGATE at his home in Concord, Calif. Geraghty is the top commenter on SFGATE. SLIDESHOW: What keeps the Bay Area talking? Keep swiping or clicking to see the moments that brought the Bay Area together. >>> less John Geraghty reads SFGATE at his home in Concord, Calif. Geraghty is the top commenter on SFGATE. SLIDESHOW: What keeps the Bay Area talking? Keep swiping or clicking to see the moments that brought the Bay ... more Photo: John Geraghty/Courtesy Photo: John Geraghty/Courtesy Image 1 of / 50 Caption Close This Concord man has been SFGATE's top commenter for years. So we talked to him. 1 / 50 Back to Gallery

His mornings start a similar way. He wakes up in his bedroom in Concord and says hello to his husband of a decade. He boots up his computer, puts on his glasses, and gets to work — by reading almost every word on SFGATE.

For the last five years, John Geraghty has been one of the top commenters on SFGATE's message boards. He checks the site several times a day; it's the first website he visits in the morning and the one he reads when he can't sleep. In the last month alone, he was the most active commenter on the site, doling out nearly 2,000 likes and dislikes and engaging in 200 conversation threads.

The 68-year-old says he often converts the website's articles into PDFs and loads them into the computer program Adobe Acrobat, where he can highlight parts that strike him without having to kill any trees.

Not all of this website's top commenters are local — at one point, one of our most prolific news commentators lived 1,500 miles away from San Francisco — but Geraghty is. The Bay Area holds a special place in his mind.

He first came to the Bay Area on a business trip in the 1970s. He picked up the San Francisco Chronicle every day; his fingers immediately found their way to Herb Caen's iconic column. When Geraghty moved back to Chicago, he begged his friend, who lived in the Bay Area, to mail him clippings of Caen's columns weekly.

In 1995, Geraghty did what he'd vowed to do — move back to San Francisco. He was moving forward after experiencing an epiphany about his sexuality and his politics. At the time, he was married — to a woman he'd been with for more than a decade and with whom he'd had two children. Then, he came out.

"My wife left, it was all my fault," he said. "It was a terrible thing, but I just had to move on. I got into therapy and I became a therapist for years. That really changed my way of thinking."

In the SFGATE comments, Geraghty has become somewhat of a vigilante, a measured-but-opinionated avatar who defends civil rights and issues of identity against the ever-growing sea of hateful language. The site receives thousands of comments of every single day, many of which are flagged as inappropriate or abusive.

Anonymous commenters have long been an integral part of SFGATE's ecosystem. This also means the comment boards can get particularly nasty. Over the last few weeks alone, more than 8,500 comments have been flagged for abuse.

Many of our reporters are threatened by name. Commenters get into vicious online arguments with threads that nearly run off the page. SFGATE moderators block users who engage in abusive language or misconduct at the rate that they can. But many of them come back with new usernames.

The fabric of anonymity breeds a vociferous kind of energy in the comments, and Geraghty has decided to encounter it daily for more than five years. But he's been around it long enough to have become somewhat of an expert. There is a certain taxonomy to SFGATE's comments section, he said, and he sorts the typical commentator into one of three categories.

The first class are those he dismisses out of hand.

"Those are the ones who will echo Trump's lies," he said. "I just try to ignore them, and they attack me many times, and that's fine. I've told several of them, I would put my education and IQ up against you, any day."

The second class, he said, are those who truly feel that they are very conservative, and they want to preserve that way of life.

"There are not a lot of centrist, conservative people left," he said. "Those are the ones I listen to; I'll heartily disagree, but they have a valid point of view."

And the third? They're like him. Progressives, liberals, perhaps some even lapsed conservatives.

Geraghty said he'd voted Republican a few times in his life but embracing his sexuality profoundly changed his ideology. He met his now-husband via Craigslist, and adopted a Mexican adult son when he lived in Guadalajara.

The last two years especially, he said, have pushed him to be even more active on SFGATE.

"I just find the national political state so frightening and so harmful to the country and to our relations around that world," he said. "Any chance I get to dispel the rumors that try to say that what we're going through is good — and having Border Patrol agents snatch babies outside of their mothers' arms is OK — I just can't tolerate that."

In the recesses of the SFGATE comments, Geraghty is a known figure. He's never met any of his friends — and foes — of the forum in real life, but he recognizes their screen names.

"I do send personal comments from time to time, when I find them to be particularly poignant," Geraghty said. "One guy had a comment last Christmas was so apropos, so funny.

"I recently sent him another comment saying, 'I still remember that comment and it makes me smile.'"

Read Annie Vainshtein's latest stories here. Email her at avainshtein@sfchronicle.com. Twittter:@annievain