Control YouTube comments: block new comments, keep old visible

Many creators, brands, and channel managers—across an estimated 50 million YouTube channels—face a recurring tension: they want to prevent future toxic or spammy comments from appearing while preserving historical discussion and social proof already visible on their videos. This is especially acute for mid-size creators (10k–500k subscribers) and brand channels that increasingly monetize content and need predictable audience environments to protect ad deals and sponsorships. You could build a subscription product (targeting the $3.0B market at roughly $60/year per channel) that provides a "freeze new comments" control plus a smart moderation layer that only applies to comments posted after a chosen timestamp, backed by transformer-based toxicity and spam classifiers and a simple audit trail for compliance and sponsor reporting. Delivery options include a lightweight browser extension, a creator dashboard that leverages YouTube APIs where permitted, and automation for bulk application across playlists/channels; the market score of 92 and revenue potential of 84 reflect strong demand and willingness to pay, while competition appears low. To stand out, focus on measurable moderation accuracy, transparent explainability for automated actions, minimal latency/UX friction, and enterprise features (sponsor-safe reports, multi-user permissions) rather than a one-off toggle. Honest challenges are material: YouTube API limits and policy risk, the cost and engineering effort to keep false positives under control, and the need to build trust with creators and agencies before charging $60+/year.