Only Frontier can do this because it is a content management system and a search engine. It knows what's unique about the page because it renders the page. Each user of the server has storage , which can be publicly accessible, private, or accessible only to members of the workgroup, or any mixture. Scripts running when pages are served can easily read and write to the user's storage area. Preferences are stored on the server.
Users can view or edit preferences thru a web interface.
Member profiles are visible to other users. Both the server and workstation are programmable thru the integrated scripting language, object database, integrated HTTP and XML support and mature editorial tools and script development tools. Visual calendars can be anywhere, allowing you to easily find out what happened on a given day. A central news page links to the days events posted by an editor or editorial team. Text is quickly editable in a web browser, and an easy XML-RPC connection to Frontier's text editor, outliner and script editor are integrated.