Entites can store arbitrary data, not just documents, images, movies, sounds, and so on. For example, a Person entity could store someone's picture, names, nicknames, phone numbers, email addresses, userids, physical addresses, registered domain names, website urls, sleeping habits, schedule, spouse's name, children's names, friends, personal likes and dislikes, bad habits, employers, and workplace address.
The Person entity should also know what emails that person sent the user, what emails the user sent that person, what webpages that person recommended to the user, what webpages the user recommended to that person, what that person's rating of a particular website is, what movies that person likes, and what other people are associated with that person. Each Person entity could also have a link to that person's own data manager.
Further, once we have Persons inside the system the user can browse them, search them, organize and reorganize them, create and delete them, and navigate through them just like any other collection of entities, all with the standard code that comes with KnownSpace. The result? A sophisticated pda or scheduler cum rolodex.
The same is true for any other class of objects the user finds interesting. We can also have Organizations and Courses and Websites and Movies and anything else the user cares about. Such entities mirror objects in our world that we organize information in our heads around. We don't have to break up all that linked information into separate bits just because today's data managers (phone book, email reader, news handler, web browser, ftp client, image displayer, and so on) each understand only one thin slice of it.
To let simpletons communicate without being aware of each other's existence the system lets them store metadata besides the usual attributes attached to entities. These marker entities can store this metadata so that it can be analyzed and clustered and evaluated just as any other entity is. Marker entities can also have their own attributes, and simpletons can modify them just as they can any other entity.
There's no limit to the kinds of entities the system could have. New entities might even be made dynamically createable by the system itself.