Well, if you do something bad, don't expect not to be punished for that foul deed. Varied on what you done, you can either get silenced, meaning you can't chat, send PM'S (Private Messages) or communicate in any way for a set period of time which is from 10 seconds to 10 years. On the rare case that you do get banned, this means you cannot play the game, it prevents you from logging in, no matter how much times you try. The time periods you can get banned are also between 10 seconds to 10 years.
One point I need to make.......
Let's say you see someone do something bad, or they are being rude to you, in order to punish them, instead for retaliating by name-calling, swearing, spamming, all that, you could just type /report. This will report that chat to the moderators (More about Moderators on it's tab) so the moderators can see what they've done, punishing them for their heinous doing.