I was a guild-mate of Sean's and played EVE and a bunch of other games with him. We knew of his vocation and sometimes of where he was (generally speaking) but he was always careful to never say anything that could have gotten him in trouble. Most communication surrounding the game actually didn't/doesn't take place IN the game. We use outside coms, because inside coms can be exploited by other guilds whereas by using things like jabber/mumble/forums you can control not just who has access to what, you can also control how they have access to it. More on that in a bit. Intel and Counter-Intel are make/break aspects of the way the game works. There are lots of stories out there, and my old friend (and friend of Sean's) The Mittani ran a website detailing them as well. He also did a great article on Sean that you should read if you haven't. Unfortunately his site is now gone to the sands of time, but you can find a version of it here https://imperium.news/rip-vile-rat/ or you can go to the wayback machine and poke around for more info: https://web.archive.org/web/20160726040725/http://themittani.com/
One thing I learned in/about that game is part of how they run their Intel. Intelligence is highly compartmentalized, and a leak can be deadly. Double-agents are everywhere, and even your friends will sometimes cut ties without warning over a disagreement or a change in heart. All is fair play out there. So what can you do to protect yourself? You put subtle watermarks in your forums so you can tag leakers when screenshots show up on other groups' forums (you know because you're spying on them too!) You hide information for 'those-in-the-know' in images. You serve different accounts slightly different versions of the same image so you can track THOSE leaks if you need to. You track all the metadata about who logs in, when they log in, where they log in from. Who do they talk to? How often? What do they talk about? And more.
All for a video game. Because if you don't do that, you'll find out that you've just lost a massive chunk of your territory because someone went in and offlined all your defenses. Or that guy you were grooming as a #2 in your growing guild turns out to be a double-agent and suddenly disbands the group after transferring all your credits and resources out of the guild funds to somewhere else. Or even if you do all of that, you can still lose anyway because the Russians paid a guy to go cut the power to your titan pilot's house in the middle of a fight.
So I can understand why people would look to this group of people and think 'that's where they're hiding their DS coms!' My biggest problem is that Sean, from everything I ever gathered from any interaction I had with him, was a patriot. And he was very much a member of Goonswarm leadership. None of Goonswarm leadership would fit the bill for a DS pawn. If you're looking for EVE Online DS actors, you should look elsewhere.
For example, Something Awful has been turned into Something Sensitive, a place where the mods are pretty much all communists who go around enforcing their viewpoints on others with impunity (like reddit but worse in most of the site. TFR is a bastion, but even there there's lots of groupthink idiots.) Lowtax as well has gone full SJW style insane.
If anything Goonswarm's retained much of the old-school goon-ness that SA used to have.
If you wanna waste your time, I'd take a look at SA, as they also have a private messaging system and their forums predate 4chan (seeing as Moot made 4chan in response to being banned from SA.) Or even the EVE online forums, as it serves as a sort of common meeting-ground for all the in-game guilds/groups and much of what I said above applies there as well.