RIAs are client/server apps that run in your browser but with desktop-like capabilities. They give users the benefits of customizable interfaces, instant feedback (no reload), and apparent performance gains (smaller chunks of the page can be generated and loaded faster than the whole page). But they come at significant costs: good old HTML and JavaScript were never really designed to do this. Flash, Java, and desktop programs are viable alternatives, but they also carry performance and usability baggage, like slow load times, loss of layout flexibility, none of the search engine optimization afforded by HTML, and non-standard widgets.

Task-focused UIs emphasize the user's core task and enable non-core tasks to be performed transparently, without losing the main focus. When shopping for houses or CDs, looking at the product listing is core, and logging in or out, putting items in your cart, or emailing friends item descriptions are non-core tasks that should be enabled transparently.

This presentation surveys the landscape of RIAs, discusses pros and cons of available RIA platforms, and delves into the technical issues involved in writing AJAX/DHTML applications and designing task-focused user interfaces with RIA characteristics.