Not sure, but if you have a problem I can always merge two or three posts together. Unless you're writing a novel, I can't see that you'd have a problem.
i've actually exceeded the character limit before, ended up having to write like 4 separate posts (although i think llama merged them into 2 that time)
Well, it's certainly not 20,520 words. Did a 513 word document, copy pasted it 40 times and I still didn't hit a cap. Got bored so stopped.
Just tried again, only I went crazy with copy/paste, then copy pasted all I copy pasted and went crazy again. All I got was the "MAP gives up, here's a white screen that won't load." We'll never know.