Once again, Amy Guy (member of the W3C Social Working Group and probably the person with sharpest analytical eye in the group) has done a fantastic breakdown of a SocialWG-related topic. This one is on the extensibility of Microformats. This is a topic of much back and forth, particularly between "Linked Data" people and "Microformats" people, and maybe Amy's post can reduce a lot of unnecessary cycling. Particularly this point is insightful:

Example debate 4

• LD: Microformats is not extensible (meaning: I can't just add my own terms and have everyone know how to use them).
• MF: Microformats is extensible (meaning: parsers are vocabulary agnostic).

... LD is talking about the vocabulary (semantics). MF is replying about the syntax. I think that's why this debate goes round in circles. I hope that clarifies something for both sides.

Way to go, Amy!