1. A preference execution system comprising: a memory; a data store component for storing schematized data and end-user specified preferences, wherein queries are evaluated and stored as data in the data store component, and constructed upon demand; a compiler to compile information agent applications including end-user specified preferences and store the compiled information agent applications in the data store; an execution engine to retrieve preferences stored in the data store upon the occurrence of one or more events and to utilize the preferences and at least one stored procedure to query tables within the data store and produce a results table, wherein the results table stores preferences whose conditions have been satisfied such that specified actions are triggered based on the stored preferences; and a context analyzer that stores and analyzes information regarding variables and parameters of a user that influence notification decision-making, the parameters comprise a user's typical locations and attentional focus, devices users tend to have access to in different locations, a user's preference as to being disturbed by notifications of different types in different settings, default parameters as to how the user wishes to be notified in different situations, and cost of disruption associated with being notified by different modes in different settings, the parameters are stored as a user profile that can be edited by the user or users can specify in real-time their state; and a constant accessor that provides navigation to data across different domains to enable a user to write cross-domain preferences.