A technique for implementing in a networked client-server environment, e.g., the Internet, network-distributed advertising in which advertisements are downloaded, from an advertising server to a browser executing at a client computer, in a manner transparent to a user situated at the browser, and subsequently displayed, by that browser on an interstitial basis, in response to a click-stream generated by the user to move from one web page to the next. Specifically, an HTML advertising tag is embedded into a referring web page. This tag contains two components. One component effectively downloads, from a distribution web server and to an extent necessary, and then persistently instantiates an agent at the client browser. The other component is a reference, in terms of a web address, of the advertising management system. The ad management system selects the given advertisement that is to be downloaded, rather than having that selection or its content being embedded in the web content page.