PETA is pretty ridiculous. It's no wonder people refer to vegetarians as retards (cheers, Iama) when their campaigns are so f**king melodramatic. It's like "Hey, I'm gonna eat your mum! How d'ya like that! Go veggie!!"
I know of a couple of people who've been swayed somewhat by PETA but on the whole they seem to be more effective at strengthening anti-vegetarian feeling (which is based mostly in a distaste for the more preachy members of the vegetarian community... Why someone would care otherwise about somebody else's diet, I don't know.)