Rich Internet Applications (RIA) is a hot topic. It seems everyone into Web and software development is talking about RIA. The Java people, the .Net people, the Flex people and the Java Script people. Each of these technologies is great for developing Rich Internet Applications. This is great for Web developers that can choose the most suitable programming language and development environment.
JavaFX will probably be released this year or the next. The JavaFX Web site highlights the new technology using the MooTools Java Script framework. Java Script with HTML, CSS, XML and the fascinating, often open source, Java Script libraries and frameworks is a great environment for developing Rich Internet Applications and has perhaps the smallest footprint.
Recently Silverlight has gained a lot of popularity. Silverlight is a true RIA environment that requires a browser plugin like Flash, Flex applications and Java applets. It works with many Internet backend technologies and it brings the programming power of the .Net languages to Web developers, even those working with the LAMP stack (Linux, Apache, MySQL, and PHP).