With clearly established leaders in this space, isn't it time we classify FaceBook, Twitter, Linked in, etc. as you do with search engines?
This is does not replace the need for:
Make Referring Domains classifiable via SAINT
http://ideas.omniture.com/t5/Omniture-Idea-Exchange/Make-Referring-Domains-classifiable-v ia-SAINT/idi-p/617
But it does mitigate it.