6. The contextual user engagement system of claim 5 , where the information extraction engine receives domain-specific rules and patterns from a user.
6. The contextual user engagement system of claim 5 , where the information extraction engine receives domain-specific rules and patterns from a user. 7. The contextual user engagement system of claim 6 , wherein an information extraction rule is based on the form of pattern variable and an action variable, wherein the information extraction rule is fired when target string in the user utterance matches the pattern variable, and wherein the action variable is used to specify a set of facts that are asserted in the context knowledge base when the rule is implemented.