Distributed Social Networking
Content objects can add 'property objects', which are of a certain type ('publishDate' etc.) and each have security settings. Something like an interface checks if necessary objects are present, and announce / treat the object accordingly. The interface can maybe also used to add multiple attribute objects at once. The interface checking probably needs to be done on a role basis, e.g. without being able to read the eventDate attribute a text doesn't become an event. People need to authenticate using their browser or reader web service, and get their role assigned.