I've been using a program that scrapes YouTube comments and adds them to my videos. I looked at my videos and all of the scraped comments are gone. I know the comments were there a couple of weeks ago, but they're nowhere to be seen now. If your program scrapes comments maybe it would be better to make it compatible with scraping comments from another video site and then posting the scraped comments on YouTube. From what I'm seeing it looks like YouTube has it's own duplicate content filter working and deleting all of them. I mean I had several videos with 500+ comments and every single comment was deleted. I might be wrong since I was not using proxies, it could just be an IP issue. I'm going to have to test this with proxies running, but that's what I've figured out so far.