IMDB keeps changing their UIs, so it's tricky to find - or maybe can't be found. I looked under HELP and at the bottom of the page, I could a current SEARCH, which was a cookie stored on this machine. But when I exit my browser, it deletes my history, and then Disk Cleanups take care of the rest.
That IMDB tracks visitors doesn't surprise me. Every website does, probably. I'd be shocked if websites - especially free ones - don't track with some notion of selling the info or gaining some monetary cost-offset.
That some websites make this clear, while others don't acknowledge it, shouldn't delude us from knowing we're all tracked, all the time, on every website.