Worst thing that ever happened to you on IMDb?
This was around 2008 or 2009... I had maintained a very steady IMDb account, was contributing reviews, etc.
I was getting a bit annoyed at trolling, but I noticed nothing much was actually done about it, in comparison to moderating regular users.
I made a reply in a topic on that Help board outlining how IMDb has no actual reason to ban trolls on a regular basis (just here and there), because their constant presence and all the responses to them guarantee a higher traffic rate, which is good for pulling in advertising dollars.
My entire posting history was wiped in less than 30 minutes. I had to reauthenticate as well.
I then removed all my reviews and vowed to never contribute another thing to IMDb.