On targetting each vendor individually: ---------------------------------------
TypePad uses Atom for editing category lists, typed
lists and photo albums. They have come up with a
mishmash of extension elements some of which are taken
from existing RSS extensions and some that are in a
SixApart specific namespace. They have also added at
least one new URI end point which isn't in the spec
(CategoryURI) although I notice there's an open Pace
about it.
It is highly unlikely that a vendor that wants to
implement similar APIs for their own service will
simply copy SixApart's extensions wholesale especially
if their implementation of some of these concepts
differs slightly from SixApart's.