On YouTube What Does It Mean When Something Is Flagged as Spam?by James Wright
YouTube is as much a social network as it is a hub for videos of all kinds, and users can comment on just about any video they see, adding their own thoughts or replying to others. You may occasionally see comments that are flagged as spam and hidden from view. While spam tends to be self-explanatory, YouTube handles spam comments in a unique way, giving other users control over what comments can and can't be seen.
Flagged As Spam
When a comment has been marked as spam, it means that enough users flagged that comment to hide it from view. As a result, the comment is hidden by default, though you can click to view it anyway if you want. With enough flags, the comment will also be reviewed by YouTube's staff, who will decide whether it warrants action.
What Is Spam?
YouTube defines spam as anything that can "cause a negative user experience by making it difficult to find more relevant and substantive material." This can mean spam from bots and people trying to sell things, but also inflammatory comments such as abuse or trolling. This is done to try to maintain civility, though many who have visited any YouTube video may attest that its effectiveness is questionable. However, YouTube staff constantly review spam reports and ban offending accounts.
While YouTube's staff reviews reports and hands out bans, YouTube users still have some influence over what comments are reported as spam. For example, it takes many reports of the same comment to mark it as spam. Even after a comment has been flagged, other users can click "Not Spam" on that comment if they don't think it counts. This helps prevent people from flagging comments they simply disagree with or don't like.
People who submit comments that YouTube confirms as spam will generally be banned from YouTube and prevented from creating another account. Videos can still be watched, but banned users have no influence over comments, flags or anything else. On the other hand, people who misuse the flagging system can also get banned. If you flag too many comments that clearly are not spam, or if you encourage others to flag comments or videos as spam, your account can be banned as well.