First of all, the "historical" "potential nomenclature confusion" mentioned in
http://cvs.openacs.org/cvs/*checkout*/dotlrndoc/www/doc/nomenclature.adp?rev=1.3&root=dotlrn must be resolved which can still be seen in messages like dotlrn.Join_A_Group .
Furthermore, I think it is not useful to try and totally ignore the competitor SharePoint where "subsite" is a central concept.