2. A method as in claim 1 , wherein the steps of presenting collectively include operating a simulation engine having a set of state variables, and having a set of rules describing permitted changes in value of those state variables, wherein substantially each collection of possible values for the set of state variables defines a context; and the set of decision models collectively include a set of behavior models, each capable of responding to a query from the simulation engine and capable of generating a response to that query.
3. A method as in claim 2 , wherein the simulation engine includes a set of features, each either defined by a current context or associated with a set of information from outside the simulation engine.