
When you click a link on a web page, your web browser makes a request to a web server which usually results in a new web page as a response. That page may have links that take you to other pages, which may in turn have more links, and so on. This model of web navigation is so common that most Internet users do little else. But as the Internet matures, this model has begun to show its age and its limitations. For web developers, for example, it less fine-grained control over the experience, and it can strain bandwidth and other resources. And for users it usually doesnt begin to approach the seamlessness and usability of good application user interfaces.