One of the Facebook documents and one of the Twitter documents are now in component form. On the Facebook doc, there are some names for section components, positing a taxonomy. These names (mostly verbs) are simply a guess, and non-exclusive (the same materials can be recombined using different names). But, IMHO, evocative. In any event, a starting point.

http://cmacc-uma.herokuapp.com/index.php?action=source&file=/Wx/com/facebook/developers/policy/Form/Doc_v01.md

Both docs live in this tree:

http://cmacc-uma.herokuapp.com/index.php?action=list&file=/Wx/com/

A theory of such trees is at:

http://new.commonaccord.org/index.php?action=list&file=/