The short answer
Target the subreddits that ChatGPT, Perplexity and Gemini already cite when your buyers ask about your category. Size is a weak signal: citations cluster in a small set of subreddits, and a mid-sized professional community often beats a huge general one. Shortlist 3 to 5 subreddits from citation data, confirm they were cited recently and by the engine your buyers use, then check that each one allows the kind of comment you plan to leave.
Steps, and what done looks like for each
| Step | What to do | Done looks like |
|---|---|---|
| 1. Write the questions | List 10 to 20 questions a buyer would ask an AI assistant about your category: comparisons, "best tool for", and the problem in their own words. | A list of questions, none of which names your brand |
| 2. Pull the cited subreddits | Describe your product in the subreddit finder, or search the subreddit list for your niche. Both rank subreddits by how often AI answers cited their threads. | 10 to 15 candidate subreddits with a citation count beside each |
| 3. Rank by citations, not members | Sort the candidates by AI citations. Drop the ones that are large but rarely cited. | A ranked shortlist; member count is a tie-breaker only |
| 4. Check the engine | Look at the split by engine. If your buyers use ChatGPT, favour the subreddits ChatGPT cites, not only the Perplexity-heavy ones. | Each subreddit tagged with the engine that cites it most |
| 5. Check recency | Keep subreddits last cited in the past 60 days. A subreddit that stopped being cited months ago is a weaker bet. | No subreddit on the list with a last citation older than 60 days |
| 6. Read the rules | Open each subreddit's sidebar and rules. Note whether it bans links, self-promotion or new accounts. | 3 to 5 subreddits where your comment is allowed |
| 7. Start in the cited threads | Answer the threads AI answers already cite, then re-check the citation counts each month. | Comments live in cited threads, and a monthly re-check on the calendar |
A worked example: a B2B marketing tool
Say you sell a B2B marketing or sales tool. Our list's marketing-and-sales and SaaS-and-startups categories hold 38 subreddits. Ranked by AI citations, the top of that shortlist looks like this. Members are blank where the list has no count.
| Subreddit | AI citations | ChatGPT | Perplexity | Gemini | Members | Last cited |
|---|---|---|---|---|---|---|
| r/SaaS | 302 | 40 | 208 | 54 | 702,778 | Oct 30, 2026 |
| r/b2bmarketing | 234 | 22 | 150 | 62 | 89,946 | Oct 16, 2026 |
| r/smallbusiness | 210 | 20 | 164 | 26 | 2,471,103 | Oct 23, 2026 |
| r/startups | 190 | 1 | 156 | 33 | Oct 23, 2026 | |
| r/sales | 126 | 11 | 104 | 11 | Oct 30, 2026 | |
| r/coldemail | 96 | 52 | 43 | 1 | 81,518 | Oct 9, 2026 |
| r/digital_marketing | 50 | 4 | 41 | 5 | 351,614 | Sep 25, 2026 |
What the example shows
- Size misleads. r/b2bmarketing has about a quarter of r/digital_marketing's members and drew 4.7 times the AI citations.
- The engine changes the pick. r/startups drew 156 Perplexity citations and 1 from ChatGPT. r/coldemail is the reverse case: ChatGPT cited it 52 times, more than Perplexity's 43.
- Recency is a check, not a filter, on this list. All seven were last cited within 60 days of the October 30, 2026 data end; r/digital_marketing is the oldest, at September 25, 2026, so recheck it before you invest there.
- For a cold email or outbound tool, the shortlist is r/coldemail, r/sales and r/b2bmarketing. For a tool sold to founders, it is r/SaaS, r/startups and r/smallbusiness.
What our data shows across all subreddits
We tracked 78,023 answers from OpenAI GPT models, Perplexity Sonar and Gemini models to buyer-style questions between January 9 and October 30, 2026. 18,549 of them (23.8%) linked at least one Reddit thread: 35,035 citations across 11,714 threads in 2,918 subreddits. Our list keeps the 1,313 subreddits cited 3 or more times. Within it, the top 10% of subreddits took 58.6% of the citations and the top 50 took 38.0%. Perplexity accounted for 68.3% of the citations in the list, Gemini 21.1% and ChatGPT 10.7%, so a ranking by total citations leans toward what Perplexity cites. 302 of the 1,313 subreddits had not been cited since before September 1, 2026.
Doing it yourself or having it done
The steps above take an afternoon with the free subreddit finder and subreddit list. The ongoing part is the work: answering cited threads every week, in a voice that each community accepts. CommunityMentions does that for $1,000 a month after a $1 setup charge, across Reddit, YouTube, Medium, LinkedIn and X; you approve the voice in Slack before anything posts. The free sample shows the comments and the subreddits we'd pick for your site.
Limits to know
- Citation counts come from the buyer-style questions we run for our clients' brands, so niches we don't serve are thin in the data.
- The list covers three engines. Claude and Google's AI Overviews are not in these counts.
- Member counts are missing for some subreddits in the list.
- A citation shows that an engine linked a thread, not that the thread changed which brand it recommended.
Sources
- CommunityMentions subreddit citation data, January 9 to October 30, 2026, as published on the subreddit list, read November 7, 2026.
- Our price and terms: pricing section and company facts, read November 7, 2026.