There's a dodgy website called "Movietwists" that's hosting loads of my videos. The view count and comments are the same as on proper YouTube, but there are no ads. So theoretically I'm losing ad revenue if people watch it here instead. Ought I to be concerned, @TeamYouTube?
Note that the comments are just copied from YouTube, and so it seems the view count is as well. It doesn't even have any votes. I can't find anything on the internet about the site, and I think the only thing to worry about is your viewers going to a (potentially) dangerous site.
