What do YouTube's comment settings do (Basic/Strict/Hold all, blocked words, link blocking, hidden and approved users, subscriber-only commenting), and what changes for viewers?

Problem: setting up moderation for a channel. Source: YouTube Help 'Learn about comment settings'. Source statements: per-video comment settings are On, Pause or Off. When On, Comment moderation options are None, Basic (hold potentially inappropriate comments), Strict (a broader range) and Hold all; held comments are kept in Studio for up to 60 days, are not public unless approved, and are available for review in over 100 languages. Comments can be limited to subscribers and paid members, with a minimum subscription time (any duration, 1 hour, 1 day, 1 week); this is not available at channel level. Channel-level: hidden users (their comments are hidden across all videos; they also cannot create clips), approved users (comments published automatically and not filtered for blocked links, words or inappropriate content), blocked words (comments containing or closely matching them may be held up to 60 days; live chat messages with them are blocked), blocked comments with links (links held for review, not for you, moderators or approved users; live chat links blocked). Hidden users, blocked words and link blocking apply to all videos and the channel homepage; they cannot be set for one video. Defaults for new uploads can be set and do not change existing videos. Effects on viewers (inference): held comments appear late or not at all; broad word lists can hide legitimate discussion; link blocking removes useful source links from viewers' comments; Pause preserves existing comments but stops new ones. Failure modes: Hold all on a busy video creates a large review backlog; setting too strict a filter lowers visible engagement. Limitations: classifiers are not described. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Descriptive; effects on viewers are inference. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://support.google.com/youtube/answer/9483359?hl=en",
      "note": "Comment settings for videos: On; Comment settings for videos: On; Blocked words; Blocked comments with links; FAQ"
    }
  ]
}