dave if we make it work on a per-instance basis, then the .info parameters simply says "supports subsite semantics", we could also have a .info parameter that says whether it does or not by default etc.
For now we could easily adopt the "supports subsite semantics" interpretation of the .info parameter, track it in the site node map, and not bother implementing any code to make it optional on a per-instance basis (no admin UI) and think about doing that later. But I'd rather we think a bit more generally first and if we think there's any use for making dual-purpose packages possible (as I mention for portal) go ahead and support it in the datamodel from the beginning.
On the other hand, the .LRN/portal mating is a kludge and it may be I'm being too complex in my thinking...
