That was asked a long time ago and per Chops it is by design. The system translates @ to "at" to prevent bots from scraping email addresses from you site.
-- Six Demon Bag Jack Burton: Hey, what more can a guy ask for? Egg Shen: Oh, a six-demon bag! Jack Burton: Terrific, a six-demon bag. Sensational. What's in it, Egg? Egg Shen: Wind, fire, all that kind of thing!