A page update handler, which may be loaded by a web browser as part of a web page, adds functionality for dynamically updating the web page with content supplied by a content server. In one embodiment, when a mouse-over event occurs with respect to a recognized item on the web page, such as a hyperlink that matches a particular link signature, the page update handler displays a corresponding overlay display object within the web page. The overlay display object displays information about or associated with the recognized item, and may provide functionality for the user to further interact with the content server. In one embodiment, an operator of a web site that is separate from the content server can enable overlay display objects within its web pages by merely adding an update handler tag to one or more corresponding HTML documents.