We've been thinking about the different aspects of social media conversations, and how to characterize them in a useful and purposeful way. 

One dimension might the following:

• "substantive" communications (relevant to a specific field)
• "responsive" communications (relevant to a specific dialogue or situation)
  

They're not mutually exclusive; in fact the best conversations combine both.  But they are distinct values that seem more relevant to social media than to traditional media. 

Striking the right balance, and combining them in a natural way, is the key to success in social media.  Beth Kanter points out that if you have a predetermined message (i.e. "substantive" communication) that you want to impose on the conversation, you nevertheless must reframe the message as a response to a need or question, in order to engage in conversation.  It's a switch in POV that's sometimes difficult to make.