Social marketers shouldn't forget about the importance of a user's e-mail inbox, writes Stephanie Miller. Social sites will always need an e-mail component to provide a back channel for less public and less uncontrolled communication, Miller writes, so many e-mail marketing techniques can be adopted directly by social marketers. "Social media is public and frantic and loud. E-mail is private and controlled and secure. For that reason, e-mail will continue to be a hub for our social activities," she adds.