Tags

Tags sit in the upload form as a list of keywords describing the video. YouTube's recommendation system works by finding videos for viewers, so distribution is earned by satisfying the people who already clicked, and no arrangement of a keyword field substitutes for that.

Tags describe your upload. They do not instruct YouTube where to place it. That is why copying the tag list off a big channel's video achieves nothing. Where the field does earn its keep is disambiguation: a channel name people spell three ways, a product code, a term with a common misspelling. Fill it in quickly and put the time into the title and thumbnail.