Schfifty has mentioned in the past about comments disappearing, and now I'm actually starting to notice that too - particularly when there's videos that say they have 100+ comments on them, but there's only like five. I'm wondering if YouTube has been removing comments from channels that aren't linked to Google+ accounts, because I've noticed pretty much every comment I've ever made on a video on my old goof-off channel (even on my own uploads) are now completely gone, and I never linked a Google+ account to that channel, because I never wanted or needed one.