Usually less than 5% of viewers leave comments on videos. Some leave thumbs up or down, but not everyone wants to leave comments and their ID's onto watched videos. In Youtube's criminal theft of my videos for years, I never even get to see comments or know that people may have been asking for help. Look at the 351 unseen comments, and the 351 additional comments/ w links or all caps that go into spam, and have never been seen because Youtube's criminal theft of these views for monitization and their greed, has deleted these views off of these videos.