Methods for enhancing content objects within web pages use persistent content identification to identify content signals and associate behaviors with the content signals, such as controlling rendering of the content signals along with other information, such as advertising. One method executes within a user device and automatically inserts code within the web page to fetch remote information used in connection with rendering the content signal in a web page. Another method operates on a server and enhances a content object so that it will have certain behaviors when downloaded and presented with a web page.