Big Forums vs. Small Chats: Where Engagement Actually Lives

The 90-9-1 Rule Is a Symptom, Not a Law

Here's a number that should haunt every community manager: In four digital health networks with 63,990 users generating 578,349 posts, fewer than 25% of members ever made even one post. The top 1% of users produced 74.7% of all content (JMIR). That's the participation inequality problem, often called the 90-9-1 rule. But here's the thing: This isn't a law of nature. It's a design failure. When you build a giant forum and expect people to jump into a sea of strangers, you get lurkers. When you build a small, focused chat, you get engagement. The data backs this up. A 2025 study across six platforms found that smaller platforms foster richer, more sustained interactions, while larger platforms drive broader but shorter participation (Scientific Reports). So if your engagement strategy is "get more members," you're solving the wrong problem.

Option 1: The Big Forum (Reddit-Style)

Big forums like Reddit's r/science have scale. They also have a participation problem. A randomized field experiment across 2,190 r/science discussions found that prominently posting community rules improved first-time commenters' compliance by 8.4 percentage points and increased newcomer participation by about 70% (PNAS). That's a real win. But here's the catch: That experiment worked because r/science already had a massive audience and a team of moderators. For most communities, you don't have that. You have a small group of passionate people and a lot of lurkers. Big forums can work if you have the resources to moderate heavily and the content to attract newcomers. But they're a treadmill. You constantly need new members to replace the ones who drift away, and the larger the audience, the more toxic the norms can become. An analysis of six multilingual Telegram communities found that users' toxicity tends to align with the prevailing norms of each chat, with 'conformist' users who match local norms representing the majority (Scientific Reports). So if your big forum has a few toxic users, the whole place can slide.

Option 2: The Small Chat (Discord-Style)

Small chats, like Discord servers, are a different beast. Interviews with 25 active Discord users identified 21 design elements that align with Oldenburg's 'third place' concept—spaces that aren't home or work, where people hang out casually and build community (arXiv). These include themed spaces for repeated interaction, user customization, and casual low-pressure engagement. The result? People actually talk. In a study of 300 young people in anime/comics/games communities, belongingness positively correlated with participation intensity (r = 0.41) and self-esteem (r = 0.36), and negatively with loneliness (r = -0.39) (Frontiers in Psychology). The key is that small size creates a sense of safety. A survey of more than 1,200 LGBTQ+ young people found 44% feel 'very safe' expressing their identity online versus 9% in person, and 61% described online spaces as 'very kind' versus 23% for in-person settings (Born This Way Foundation). That's not going to happen in a mega-thread.

Comparing on Three Criteria

Let's be concrete. I'm comparing a Reddit-style forum with a Discord-style chat on three criteria: participation rate, quality of interaction, and moderation burden.

Now, who is each for? Big forums are for communities that need to reach a huge audience—think support groups for rare diseases or open-source projects. They're also for communities that can afford heavy moderation. Small chats are for most other communities, especially those focused on building deep relationships. For example, a diabetes support group on Facebook found that roughly two-thirds of posts included unsolicited sharing of self-management strategies and almost 29% offered emotional support (Diabetes Facebook groups). That kind of support doesn't happen when you're one of 10,000 members. It happens when you're one of 50.

The Hidden Cost of Small: Misinformation and Echo Chambers

Small chats have a dark side. They can become echo chambers where misinformation spreads unchecked. A content analysis of 1,534 statements across 144 threads in two Italian mental health Facebook communities found that 26.1% of comments contained medically inaccurate information, and nearly 60% of threads contained misinformation that was never corrected (JMIR). That's terrifying. But here's the counterintuitive part: Small groups can also correct misinformation faster. A BMJ content analysis of 4,600 postings to a breast cancer mailing list found only 10 (0.22%) contained false or misleading information, and seven of these were identified and corrected by other members within hours (BMJ). The difference? The mailing list had a close-knit community. The Facebook groups were more diffuse. So the problem isn't size per se—it's whether members feel responsible for the group's health. In small chats, they do.

Quick tip: If you run a small chat, don't just let anyone in. Gatekeeping is good. It creates a sense of safety and shared purpose.

What I'd Actually Do

Start small. If you're building a new community, don't launch a forum. Launch a Discord server or a WhatsApp group with a clear purpose and a cap on members—maybe 100 to 200. Use the design elements that Discord nailed: themed channels, customization, and low-pressure spaces for casual chat. Encourage repeated, casual interaction. That's what builds a 'third place' (Social Media + Society). And don't obsess over the 90-9-1 rule. It's a description of what happens in big, badly designed spaces, not a mandate. The data is clear: informal, naturally occurring peer support is more effective for mental health than formal support from trained peers, and apps, social networking sites, and video conferencing outperform lower-interactivity formats like forums and email (Epidemiology and Psychiatric Sciences). So if you want engagement, you need interactivity. Small chats deliver that. Big forums don't.

Here's a concrete example: A randomized trial of 90 adolescent and young adult cancer patients found that an 8-week group online-based peer support intervention significantly improved psychological distress, anxiety, and depressive symptoms (Supportive Care in Cancer). That was a small group, not a giant forum. Imagine trying to replicate that with a Reddit thread. You can't.

So, my recommendation: If you're starting a community, start small. If you're already big, break it into smaller sub-communities. Create spaces where members know each other's names. That's where engagement lives.

Sources

• JMIR - https://pubmed.ncbi.nlm.nih.gov/24496109/
• Scientific Reports (2025) - https://www.nature.com/articles/s41598-025-24545-z/tables/3
• PNAS - https://www.pnas.org/doi/10.1073/pnas.1813486116
• arXiv - https://arxiv.org/abs/2501.09951
• BMJ - https://pmc.ncbi.nlm.nih.gov/articles/PMC411092/
• Epidemiology and Psychiatric Sciences - https://pmc.ncbi.nlm.nih.gov/articles/PMC11886969/