Comment moderation on main site

Anyone know what triggers a comment to go into the queue for moderation?
And then why would it get deleted?

I’ve had a couple that needed moderating, and then sometimes they just disappear. Does it have to do with links? Or are there other trigger words that you’re just not allowed to say?

Yes, last time I had one of my comments in moderation the trigger where links (to the help center and Viki twitter). They are trying to find a way to block certain messages and unfortunately it block the good messages sometimes too. That’s what I’ve been told when I asked Viki.