#radicalization

Think of Friendster's "fakester" problem, driven by its designers' beliefs about how people should organize their affinities:

https://www.zephoria.org/thoughts/archives/2003/08/17/the_fakester_manifesto.html

Or Mastodon's initial, self-limiting ban on "quote" posts as a way to encourage civility:

https://blog.joinmastodon.org/2025/02/bringing-quote-posts-to-mastodon/

And, as the paper's authors note, Stack Overflow has a strict prohibition on overlapping new communities, echoing Usenet's original design dispute.

On its face, this hierarchical principle for conversational spaces makes sense. Viewed through a naive economic lens of "reputation capital," having one place where all the people interested in your subject can be reached is optimal. The more people there are in a group, the greater the maximum "engagement" – likes, comments, reposts. If you're thinking about communities from an informational perspective, it's easy to assume that bigger groups are better, too: the more users there are in a topical group, the greater the likelihood that a user who knows the answer to your question will show up when you ask it.

But this isn't how online communities work. On every platform, and across platforms, overlapping, "redundant" groups emerge quickly and stick around over long timescales. Why is this?

That's the question the paper seeks to answer. The authors used data-analysis techniques to identify overlapping clusters of Reddit communities and then conducted lengthy, qualitative interviews with participants to discover why and how users participated in some or all of these seemingly redundant groups.

They conclude that there's a community-member's "trilemma": a set of three priorities that can never be fully satisfied by any group. The trilemma consists of users' need to find:

a) A community of like-minded people;

b) Useful information; and

c) The largest possible audience.

The thing that puts the "lemma" in this "trilemma" is that any given group can only satisfy two of these three needs. It's hard to establish the kinds of intimate, high-trust bonds with the members of a giant, high-traffic group, but your small, chummy circle of pals might not be big enough to include people who have the information you're seeking. Users can't get everything they need from any one group, so they join multiple groups that prioritize different paired corners of this people-information-scale triangle.

The interview excerpts put some very interesting meat on these analytical bones. For example, economists typically believe that online marketplaces rely on scale. Think of eBay: as the number of potential bidders increases, the likelihood that one will outbid another goes up. That drives more sellers to the platform, seeking the best price for their wares, which increases the diversity of offerings on eBay, bringing in more buyers.

But the authors discuss a community where vintage vinyl records are bought and sold that benefits from being smaller, because the members all know each other well enough to have a mutually trusting environment that makes transactions far more reliable. Actually knowing someone – and understanding that they don't want to be expelled from the community you both belong to – makes for a better selling and buying experience than consulting their eBay reputation score. The fact that buyers don't have as many sellers and sellers don't have as many buyers is trumped by the human connection in a community of just the right size.

That's another theme that arises in the paper: a "just right" size for a community. As one interviewee says:

I think there’s this weird bell curve where the community needs to be big enough where people want to post content. But it can’t get too big where people are drowning each other out for attention.

This explains why groups sometimes schism: they've gone from being "just big enough" to being "too big" for the needs they filled for some users. But another reason for schism is the desire by some members to operate with different conversational norms. Many of Reddit's topical clusters include a group with the "jerk" suffix (like r/climbingcirclejerk), where aggressive and dramatic forms of discourse that might intimidate newcomers are welcome. Newbies go to the main group, while "crusties" talk shit in the -jerk group. The authors liken this to "regulatory arbitrage" – community members seeking spaces with rules that are favorable to their needs.

And of course, there's the original source of community schism: specialization, the force that turns rec.pets.cats into rec.pets.cats.siamese, rec.pets.cats.mainecoons, etc. Though the authors don't discuss it, this kind of specialization is something that recommendation algorithms are really good at generating. At its best, this algorithmic specialization is a great way to discover new communities that enrich your life; at its worst, we call this "radicalization."

I devote a chapter of my 2023 book The Internet Con, "What about Algorithmic Radicalization?" to exploring this phenomenon:

https://www.versobooks.com/en-gb/products/3035-the-internet-con

The question I grapple with there is whether "engagement-maximizing" algorithms shape our interests, or whether they help us discover our interests. Here's the thought-experiment I propose: imagine you've spent the day shopping for kitchen cabinets and you're curious about the specialized carpentry that's used to build them. You go home and do a search that leads you to a video called "How All-­Wood Cabinets Are Made."

The video is interesting, but even more interesting is the fact that the creator uses the word "joinery" to describe the processes the video illustrates. So now you do a search for "joinery" and find yourself watching a wordless, eight-minute video about Japanese joinery, a thing you never even knew existed. The title of the video contains the transliterated Japanese phrase "Kane Tsugi," which refers to a "three-­way pinned corner miter" joint. Even better, the video description contains the Japanese characters: "面代留め差しほぞ接ぎ."

So now you're searching for "面代留め差しほぞ接ぎ" and boy are there a lot of interesting results. One of them is an NHK documentary about Sashimoto woodworking, which is the school that Kane Tsugi belongs to. Another joint from Sashimoto joinery is a kind of tongue-and-groove called "hashibame," but that comes up blank on Youtube.

However, searching on that term brings you to a bunch of message boards where Japanese carpenters are discussing hashibame, and Google Translate lets you dig into this, and before you know it, you've become something of an expert on this one form of Japanese joinery. In just a few steps, you've gone from knowing nothing about cabinetry to having a specific, esoteric favorite kind of Japanese joint that you're seriously obsessed with.

If this subject was political rather than practical, we'd call this process "radicalization," and we'd call the outcome – you sorting yourself into a narrow niche interest, to the exclusion of others – "polarization."

But if we confine our examples to things like literature, TV shows, flowers, or glassware, this phenomenon is viewed as benign. No one accuses an algorithm of brainwashing you into being obsessed with hashibame tongue-and-groove corners. We treat your algorithm-aided traversal of carpentry techniques as one of discovery, not persuasion. You've discovered something about the world – and about yourself.

Which brings me back to that original, Usenet-era schism over "redundant" groups. The person who wants to talk about being a "gourmand" in the "rec." hierarchy wants to participate in a specific set of conversational norms that are different from those in the "talk." hierarchy. Their interest isn't just being a "gourmand," it's in being a "rec.gourmand," something that is qualitatively different from being a "talk.gourmand."