There are different platforms for building rich internet applications:
 

Adobe Flex

Adobe Flex is a collection of technologies released by Adobe for the development and deployment of cross-platform rich Internet applications based on the Adobe Flash platform.

Adobe Air

Adobe Integrated Runtime (AIR) is a cross-platform runtime environment for building rich Internet applications using Adobe Flash, Adobe Flex, HTML, or Ajax, that can be deployed as a desktop application.
 

Microsoft Silverlight

Microsoft Silverlight is a programmable web browser plugin that enables features such as animation, vector graphics and multimedia that characterizes rich Internet applications. Version 2.0, released in October 2008, brought additional interactivity features and support for .NET languages and development tools.

SUN JavaFX

JavaFX is a software platform for creating and delivering RIAs that can run across wide variety of connected devices.
The current release (JavaFX 1.2) enables building applications for desktop, browser and mobile phones. TV set-top boxes, gaming consoles, Bluray players and other platforms are planned.

Extending Capabilities:

JavaScript Libraries and Toolkits:

-         DOJO: The Dojo Toolkit offers rapid, modular development with great tools to test and optimize production performance, with no compile step. http://dojofoundation.org/#tab-DojoToolkit

-         Jquery: JQuery is a fast and concise JavaScript Library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development. http://jquery.com

Standards and Concepts

-         HTML 5: This latest specification evolves HTML and its related APIs to ease the authoring of Web-based applications. http://www.whatwg.org/specs/web-apps/current-work/

-         Semantic Web: the Semantic Web is the extension of the World Wide Web that enables people to share content beyond the boundaries of applications and websites. It has been described in rather different ways: as a utopic vision, as a web of data, or merely as a natural paradigm shift in our daily use of the Web. http://semanticweb.org/wiki/Main_Page 

 The next post will compare the challenges of the different RIA platforms.

What is your preferred RIA building platform?