techcrunch.com: Remembering Email — Warum die E-Mail das ultimative soziale Tool ist. Strategically, social has many more attributes that heighten the value of individual objects. These include comments, Likes, retweets, @mentions, and direct messages. Given their integration of citation and identity, these signals move beyond CCs and BCCs to build a sense of social traction that carries with it a history and context for new messages.