Web 2.0 brings with it new opportunities for deploying highly interactive webpages. A challenge for Web 2.0 developers is capturing information to document the user experience. Client-side dynamic metadata provides one solution to capturing and logging information on the client-side, while lowering the bandwidth requirements for communication with the server. This paper discusses the architecture of a proof-of-concept system, the Dynamic Metadata Prototype. The architecture is described as an AJAX Design Pattern.