Hello,
we have recently implemented a project for a customer that required adding structure to Share sites. What we did is implement different site types (e.g. a departmental site and a site for teams within a department), that allowed the site creator / manager to specify a site as the superior anchor via the create / edit site dialogs. The flat-list structure of sites was kept as Alfresco bases a lot of functionality on this, but we added a secondary structure with hierarchies to this. A new, static component on user and site dashboards (not a dashlet) provides a navigation tree for the site hierarchy.
In terms of naming, we added secondary name attributes, such as a department symbol (short form label, much like a stock symbol in an stock exchange), and the option to configure which type of name would be displayed in the new navigation tree component. The base site name attributes shortName and title were kept and still retain their standard function, i.e. unique, technical identifier and human-readable full name.
The most recent feature implemented was the aggregation of wiki articles over the site hierarchy, e.g. all visible wiki articles from site ancestors and site descendants would be displayed in a site wiki, with the added information of origin. Additionally, the linking feature was enhanced to allow cross-site linking of wiki articles.
Regards
Axel