Another problem with trade and general chat is the feeding of trolls. Perfectly decent people will get into a rage war because Trollmaster and Trolliscious demeaned a class, profession, race, favorite sports team, etc. Trolls love that. Any attention is good. And then everyone else has to put up with the arguing and insults flying back and forth. I know. It's hard to ignore when the trade chat villains start calling anyone who likes the female pandaren "chubby chasers," but going verbally postal in public chat isn't going to help anyone. I fought the urge and so can you. (Though my Twitter followers heard all about it.)
Guild masters and officers often keep trade chat on to make sure that no guildies are misbehaving in public. This can be a painful experience and usually not worth the time. Personally, I turn public chat off in live and keep it on in beta. Beta general chat often answers questions I have -- in between all the misogyny and malicious pranks.
Do you turn off the public chat channels? If so, do you turn them back on again to conduct legitimate business, or do you just stay away? Do you find chat problems in other MMOs? Or are you one of the ones causing the problem? /glare