Each letter, number, space, or symbol you type is a character.
The character limit mean you must type at least 24 letters, numbers, spaces, or symbols to meet one of the criteria of Non-Spam posts.
The other criteria is that you don't post off topic, and that you post at least 4 words so even "That was supercalifragilisticexpialidocious!" is spam.
Bypassing is bad too. That meas "Tis so very cool *fillerfiller*" or anything of that nature is spam. The only place that is accepted is in Profile Messages and certain forums.