What do pinned comments and creator hearts do on YouTube, what do viewers see, and what does the comment preview limit?

Problem: using comments to guide the conversation. Source: YouTube Help 'Post & interact with comments'. Source statements: a creator can pin their own or a fan's comment to the top; pinning needs advanced features (up to 24 hours to appear); pinning a new comment replaces the old one; unpinning returns the comment to its place; on computer viewers see a 'Pinned by' icon with the channel name, on mobile they must expand the comment section to see it. A heart shows appreciation for comments (watch page and Posts tab); the viewer sees the creator's avatar with a small red heart and, depending on their settings, a notification that the channel owner 'loves your comment'. The comment preview shown on mobile may include recent, pinned or hearted comments; because space is limited, pinning does not guarantee appearing in the preview, although the pinned comment is first when the full list is opened; moderation settings (blocked words, hidden users) also apply to the preview. YouTube may also show a reminder before posting when a comment could be offensive (English and Spanish only). Method (inference): pin a comment that answers the most common question, corrects an error or links the sources, since it is the first comment readers see; hearting is a cheap acknowledgement signal. No effect on ranking or watch time is documented. Limitations: nothing here shows pinning or hearts change engagement; do not claim it. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Documents mechanics only; any engagement effect is undocumented. 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/6000964?hl=en",
      "note": "Pin comments to the top; Pin comments to the top; Add hearts to favorite comments; Comment previews FAQ"
    }
  ]
}