Facebook as a Gmail killer? Not quite. But Facebook took its first foray into traditional messaging when it let users obtain a @facebook.com e-mail address in November, part of a revamp to the site's messaging features. But unlike Google's Gmail e-mail behemoth, Facebook's messaging remains decidedly minimalistic. "This is not an email-killer. This is a messaging system that includes email as one part of it," Zuckerberg said.