12. A system for facilitating online advertising, comprising: one or more processors; an extraction component, executed by at least one of the one or more processors, that extracts a dynamic user profile from a user behavior data stream; a semantic build component, executed by at least one of the one or more processors, that correlates information from the dynamic user profile to build a semantic user profile; an indexing component, executed by at least one of the one or more processors, that indexes the semantic user profile; a modeling component, executed by at least one of the one or more processors, that generates a user ranking model based at least on machine learning; and a query processing component, executed by at least one of the one or more processors, that retrieves a set of indexed semantic user profiles in response to a received semantic query, wherein the query processing component ranks the set of indexed semantic user profiles based on the user ranking model.
12. A system for facilitating online advertising, comprising: one or more processors; an extraction component, executed by at least one of the one or more processors, that extracts a dynamic user profile from a user behavior data stream; a semantic build component, executed by at least one of the one or more processors, that correlates information from the dynamic user profile to build a semantic user profile; an indexing component, executed by at least one of the one or more processors, that indexes the semantic user profile; a modeling component, executed by at least one of the one or more processors, that generates a user ranking model based at least on machine learning; and a query processing component, executed by at least one of the one or more processors, that retrieves a set of indexed semantic user profiles in response to a received semantic query, wherein the query processing component ranks the set of indexed semantic user profiles based on the user ranking model. 15. The system of claim 12 , wherein the semantic build component further incorporates a static user profile to build the semantic user profile.