Well, when I type "subsite definition" at Google, this is the first item returned:
"Content or program areas on program sites that have their own set of unique, left navigation. Subsites must reside within one of the main program sections. However, when the user selects the subsite from the main section navigation, the section's left navigation is replaced with the subsite's left navigation."
Now ... where in this definition (or similar ones you'll find) is there anything that truly fits what our subsite package does? Where does it capture the notion that every acs-subsite defines a new community?
I suppose you might try arguing that user and community management are minor things not worth emphasizing but ... if you believe that, why use OpenACS? Why call it a *community* system? Because user and (now that we're fixing the subsite package) community management are among the most important features of the toolkit.