I remember the first time it happened. 404
I freaked out because it said user account not found and had a smiley face. I really thought somebody was deleting me, and I couldn't figure out any reason why!
But with my next post (which might have been a protest or something, it was so long ago) it vanished. It wasn't until I realized it happened at post 404 that I suspected some skullfuckery going on.
Oh you got me good with that one.