I'm not quite sure I follow, I was thinking that even collections of
URLs, for example for a link blog, would still be wrapped, possibly in
an entry like in the TypePad API, or even wrapped in XBEL.
How about looking at current usage and trying to come up with a
set of use cases?
I have started a list here:
http://www.intertwingly.net/wiki/pie/ProtocolCollectionTypes
Please add any others I've missed. Right now it is just a pure raw
data dump. After we have all the possibilites enumerated then we can
start grouping and consolidating it into one master list.