A namespace can have what are called "backing
topics." These are topics that aren't actually stored
anywhere except in the engine and they are always the
oldest version of a topic -- and they exist even if the
user has never created them.
This causes problems when trying to use a namespace
for storing purely 'data' topics - for example
a 'MyOrg.People' namespace of user HomePages, which
you want to then Import into other namespaces. The
problem arises when you Import the namespace, as
although MyOrg.People doesn't actually contain a
HomePage topic (it doesn't need one, it's just a folder
where we store a bunch of topics), the system thinks it
has one, and presents the user with a (confusing) pop-
up to choose which HomePage link to follow.
What we need, I guess, is some attribute (say within
_ContentBaseDefinition) which flags whether or not to
auto-gen the HomePage topic.
