The current Specification Guideline describes a set of categories in which most W3C specifications should fit. This page shows where the current W3C Recommendations (as of $Date: 2011/12/16 02:56:59 $) fit in this model.
Note that this document isn't the result of any consensus right now. It just here to get a better idea of how this model applies to the current state of art and to try to resolve the unsure cases (backed in green).