Planning & Prioritizing for Usability
Planning such a system requires the inculcation of a usability perspective while identifying site objectives and goals. During development we should focus on the form under development and have a clear idea of how it will function for the end user. This system should be delivered on a mental model of natural user task flow. The usability perspective in RIAs requires decisions about what functionality should execute on a new page and what is best suited to a partial page update. Incorporating user-generated content along with ratings and reviews enhances the usability of RIAs. Their design should comprehend visual perception and user behavior. Key tasks to be planned and techniques to be used in an RIA context include:

A Holistic View of RIA Controls from a Usability Perspective
Any usable RIA control can be thought of as having four characteristics:
Ability: The developer's ability to render rich and interactive control while using rapidly evolving and intuitive Web technologies.
Functionality: This characteristic is used to deliver functionality benefiting the user and business as a whole improving task time, easy input, and real-time solutions with a rich experience.
Capacity: This characteristic hints at infrastructure for rendering RIA controls with customizable and interactive solutions to the end user with enhanced experience and significant business gains.
Learnability: This hints at the designing widgets for its higher retention and recall while using it with natural ease. (Figure 2)

This fourfold usability delivers a successful and sustainable application with customer retention meeting the user's expectations while enhancing his learnability and user experience. This can help in articulating important design decisions such as deciding how much richness to add - keeping in mind how existing functionality would be enhanced - while catering to existing infrastructure needs and reducing the user's task time.

Best Practices for RIA Usability
Stick to the Basics: Before implementing RIA innovations, involve a trained usability tester to find usability flaws. Designers should redesign per usability conformance. Moreover, focus should also be on privacy and security policies and guidelines for error-handling Provide Alternatives. RIA accessibility depends on JavaScripting being enabled in browsers. Browsers should auto-detect this and redirect the user to an alternative form.

• Use AJAX to Enhance the User Experience: An RIA control should be provided if it makes a user task easier and increases learnability and efficiency. One should refrain from delivering a rich solution if the user doesn't benefit.
• Develop for Users: RIA can confuse the user. We need to develop to the target audience and objective use so the user can achieve his intended goals.
• Usability Inspection: Have a usability specialist attempt to judge RIA effectiveness on a predefined set of usability criteria to identify potential problems early. (Table 2)
• Usability Test: Participants should test effectively, evaluating design effectiveness for the task and disseminate the results for testing iterative solutions. (Table 3)
• Report: Report the essential design recommendations and fixes divided into short-term, long-term, and must-do while the features are retained as they are. (Figure 3)

Conclusion
Understanding customers is critical in delivering on the business promise of SOA. Portals and Web 2.0 have emerged crucial SOA consumer ecosystem enablers. The Web 2.0 approach to consumer RIAs has primarily focused on the richness of the controls rather than the end user. To enhance user focus, there is a need to circumvent common design flaws in RIA with universal usability guidelines following right methodologies. This vision should use the right usability tools and techniques. In this article we have discussed the diverse usability perspectives of Web 2.0 RIA systems and have discussed appropriate techniques that can help RIA developers and end users by reducing task time, user errors, user disruption, training time, maintenance, and redesign costs.

References
•  Megan Burns with Ron Rogowski and Steven Geller. Measuring Rich Internet Applications. Forester Press.
www.forrester.com/go?docid=41476.

•  Ron Rogowski with Kerry Bodine and Caroline L. Carney. Rich Internet Application Usability 101. Forester Press.
www.forrester.com/go?docid=39615.

•  Frank Spillers. "Demystifying Usability: Eye-Tracking Studies - Usability Holy Grail?"
http://experiencedynamics.blogs.com/site_search_usability/2004/12/eyetracking_stu.html.

•  Robert Hoekman, Jr. "Communicating Web 2.0 Through Design."
www.thinkvitamin.com/features/design/communicating-Web-20-through-design.

•  Deborah Abratt, Wayne Mallinson, and Antonet Bekker. "Usability Testing: Recipe for Success."
www.stickyminds.com/getfile.asp?ot=XML&id=7072&fn=XDD7072filelistfilename1.pdf.