By Brad Stone March 13, 2008 3:45 pm March 13, 2008 3:45 pm UPDATE: See clarification at the end. In the last two months, several Internet security firms have suggested that spammers had devised a way to bust the “captcha” that is protecting Gmail. This would allow them to use the popular e-mail service to drown the rest of the Internet with e-mails containing links to malware and clumsy Viagra pr