A technique is described for delivering contextual information to end users of a data network which includes at least one client system associated with an end user. According to a specific embodiment, the technique of the present invention provides a contextual-based platform for delivering to an end user in real-time proactive, personalized, contextual information relating to web page content currently being displayed to the user. A portion of web page content relating to a web page intended for display on the client system is received. According to a specific embodiment, the web page corresponds to a URL associated with a content provider. The portion of web page content is analyzed for keyword information. A portion of keyword information associated with the portion of web page content is identified. According to a specific embodiment, the portion of keyword information includes at least one keyword. Contextual information to be delivered to the end user is selected using the portion of keyword information. According to a specific implementation, the contextual information corresponds to ad information which is provided by a campaign provider server system. A set of web page modification instructions is generated using the contextual information. According to a specific embodiment, the set of web page modification instructions includes instructions for modifying the web page content to include the selected contextual information. The set of web page modification instructions is provided to the client system to thereby cause the portion of contextual information to be delivered to the user. According to a specific embodiment, when the client system implements the web page modification instructions, the web page content is caused to be modified in a manner which results in a display of contextual information on the client system.