Most idea-hunting guides send you to the same two places: Reddit and Twitter. Both are real sources, but they're also the most saturated — every other founder scanning for ideas is reading the same threads you are. The six sources below include the obvious ones, but the value is in the ones most people skip, especially the one buried at the bottom of every App Store listing.
1. Reddit — professional subreddits
What makes it rich: Not r/SaaS or r/Entrepreneur, which are full of people pitching ideas rather than describing problems — the gold is in profession-specific communities: r/msp, r/bookkeeping, r/realtors, r/dental, r/Etsy. These are people doing the job, complaining about the job, in language no marketer wrote.
What to search for: Switching and workaround phrases — "alternative to," "built my own spreadsheet for," "cobbled together." Filter to threads with real reply chains, not just upvotes; a comment thread means people are actually debating the problem.
Failure mode: The big generalist subs are drowned in "what SaaS should I build" posts from other founders, not real practitioners. If the poster's username history is all startup talk, discount the signal.
2. Hacker News — Ask HN and Show HN
What makes it rich: A technically sophisticated, high-intent audience that's unusually candid about tooling gaps, and Show HN threads double as a live library of what's already been tried (and where the comments say it falls short).
What to search for: Ask HN threads titled around "what do you use for X" pull in dozens of comparison answers in one place — a free market map. On Show HN launches, the top comment is often the real, unfiltered gap the built product didn't cover.
Failure mode: The audience skews toward developer tools and infrastructure; pain from non-technical professions rarely surfaces here, so treat it as one lens, not the whole picture.
3. Stack Exchange — softwarerecs and webapps
What makes it rich: The softwarerecs.stackexchange.com community exists for exactly one purpose — people posting "is there a tool that does X" with strict formatting rules that force them to be specific about requirements and budget.
What to search for: Unanswered or thinly-answered questions. A well-answered question means the market gap is already filled; a question with zero good answers after months is a much stronger opportunity signal.
Failure mode: Low volume compared to Reddit or HN, and strict moderation means some real questions get closed as "off-topic" before they gather any engagement — don't mistake low reply counts here for low demand.
4. App Store reviews — 1★ and 2★
What makes it rich, and why it's the one everyone skips: This is the single most underused source, and it shouldn't be. A 1★ review is written by someone who already pays for a tool in your target category, used it enough to form a strong opinion, and is now unhappy enough to write publicly about it. That's not hypothetical pain — that's a customer with an active budget line and a documented reason to leave. Reddit threads are full of people who've never opened their wallet for anything in the category; App Store reviewers, by definition, already have.
What to search for: Reviews of the 3-5 most popular tools in your target category, filtered to 1-2★. Look for repeated, specific complaints — not "buggy" or "crashes," but named missing features or workflow gaps that show up across multiple independent reviewers.
Failure mode: A lot of low-star reviews are pure venting with no actionable gap ("worst app ever"). You have to filter for the reviews that name a specific missing capability, not just frustration.
5. GitHub Issues
What makes it rich: Feature requests filed by developers are unusually precise — they've already thought through the shape of a solution, and reaction counts (👍) on an issue are a clean, spam-resistant proxy for how many other people want the same thing.
What to search for: Open issues on popular open-source tools tagged "feature request" or "enhancement" with high reaction counts and no maintainer commitment to build it — that gap between demand and roadmap is your opening.
Failure mode: Skews heavily toward developer-facing problems and tooling for other developers; less useful for finding ideas outside the technical/dev-tools space.
6. Lobsters
What makes it rich: A smaller, more curated developer community than Hacker News, with less noise and a userbase that tends to write thoughtfully about tooling gaps in comments rather than just linking articles.
What to search for: Comment threads on infrastructure and tooling stories, filtered for solution-seeking and workaround phrases. The lower volume means less to sift through, but also a tighter signal-to-noise ratio.
Failure mode: Very low volume compared to every other source on this list — treat it as a confirming source, not a primary one, unless your niche is squarely developer tooling.
Someone who is angry enough to leave a 1★ review has already done the hardest part of market validation for you: they paid.
The pattern across all six: the richest signal isn't where the most people are talking, it's where the talkers have already proven something about themselves — that they pay for tools in the category, that they've tried and failed to solve it themselves, or that they've formally requested the exact feature you're considering building. Volume without that proof is just noise with better SEO.
Manually rotating through six sources every day isn't realistic for a solo founder — so BuyerTell automates it. It mines all six (Reddit via OAuth across 30+ professional subreddits, Hacker News, Stack Exchange's softwarerecs and webapps, App Store 1-2★ reviews, GitHub Issues, and Lobsters), scores every signal with the intent-weighted formula covered in buyer-intent signals, and has Claude Opus 4.8 synthesize three evidence-grounded idea briefs every morning. See how the full approach compares to GummySearch, which mined Reddit alone.
If you only have an hour this week, spend it on App Store reviews for the two or three incumbent tools closest to your niche. It's the source with the least competition from other idea-hunters, and the highest concentration of people who've already proven they'll pay.