1. A method in a wearable computer for an executing user characterization system to provide information about a current state of a user of the wearable computer, the user characterization system modeling the current state with multiple state attributes and including state server modules (SSMs) to supply values for the state attributes, state client modules (SCMs) to process values for the state attributes, and an intermediary module to facilitate exchange of state attribute values, comprising: under control of each SSM, generating values for at least one of the state attributes and sending the generated values to the intermediary module; under control of each SCM, receiving values for at least one state attribute from the intermediary module and performing processing based on the received values; under control of the intermediary module, facilitating exchange of values by, receiving values for the state attributes from SSMs and from a first of multiple other characterization systems, each of the other characterization systems executing on another computer to model a current state related to the another computer; for each state attribute, storing the received values for the attribute; and receiving requests for values of indicated state attributes from SCMs and from a second of the other characterization systems, and sending stored values of the indicated state attributes to the SCMs and the second other characterization system; and modeling an aspect of a current state using distributed state information by, identifying multiple portions of the distributed state information needed for the modeling of the aspect, and identifying multiple of the other characterization systems each having access to one of the identified multiple portions; gathering the identified portions of the distributed state information from the identified other characterization systems; and generating at least one value for the modeled aspect based on the gathered portions of the distributed state information, so that the user characterization system can interact with other characterization systems in order to exchange and use distributed state information of interest.