A message board posting technique designed to end or derail threads that its user finds uninteresting or lacking productive discussion. This technique involves posting screencaps from the 1967 Spider-Man cartoon series with humorous captions unrelated to the original thread topic. The user generally initiates a Spiderman thread with captions intended to declare that the original thread topic will no longer be discussed. Occasionally, additional users contribute to the derailing with their own screencaps of Spider-Man. Frequently used on 4chan's various message boards, where the technique originated. Generally used to derail threads about incest or "wincest."

It’s an acronym standing for Can’t Remember A Fucking Thing. It’s usually used to describe embarrassment at being unable to remember someone (CRAFT moment); going onstage as the lead in the latest theatrical performance and your mind goes completely blank (CRAFT situation); the next morning after a night when you got pissed as a fart and woke up in bed cuddling a traffic cone and a string of fairy lights wound round your prick.

Spiderman threads are pretty much the best thing ever. The definition is self-explanatory.