Investor’s Business Daily – E-mail systems such as Yahoo and Google are gearing up to offer social networking through their users’ mail. The companies are trying to make accounts into personalized home pages to challenge current social networking such as MySpace and Facebook. In people’s pre-existing e-mail accounts already lies the key to a social network — a social graph, which is the connections you make while you e-mail your friends. With that in place one’s e-mail may soon offer much more.