Of course, /ignore still works, and my little level one Tauren now has a bigger /ignore list than any of my other toons, thanks to some rowdy spammers yesterday. And /leave General will get you out of Barrens chat (just as /join General will get you back in when you finally arrive in Ashenvale). And I don't have that much of a problem with this stuff (only when I group up with 500 cows), but if you're really tired of chat spam, Devnull might be an addon worth looking at.
It's not real complicated-- those of you who are experts at chatting (or have just been given a headache before by all the yelling) probably already knew it. But it was definitely a helpful little tip yesterday to sort through all the spam in the channels.