26. The system of claim 19 , wherein the pre-specified link signature is a product detail page link signature associated with an electronic catalog of products.
26. The system of claim 19 , wherein the pre-specified link signature is a product detail page link signature associated with an electronic catalog of products. 27. The system of claim 26 , wherein the content server is operative to interact with the update handler code to enable a user to browse and make purchases from the electronic catalog via interactions with an overlay display object added to the web page.