The main problem with RIA is their runtime platform. Flash is the most appropriate technology for it nowadays due to its market penetration and singular target. Sadly, there are major speed and stability problems. Anything beyond simple applications need careful architecting and exhaustive testing to run acceptably. Alternatively, Ajax may seem nice for certain effects, but it will always remain an uphill battle to track down all the browser differences and work around all the specific platform bugs. I thought we learned that lesson with DHTML six years ago. Also, Ajax also totally lacks any kind of multi-media capabilities.He points out that applets might have the capabilities necessary, but the size of the JRE is a burden, and that "Java's reputation in this area has totally been compromised and that any user runs away as soon as the word applet is dropped."
Geert ends with a mention of the canvas element in Firefox and Safari - but also mentions IE7, which may not play along.
What do you think the future of rich internet applications is? Will Ajax get multimedia capabilities, or is Flash the RIA platform of the future, despite its lack of speed and stability?