Smart Contracts
http://www.erights.org/smart-contracts/index.html
http://www.waterken.com/dev/IOU/Design/
We may end up getting RESTful smart contracts for free due to all the goodness in the current design. This could lead (my client).com to an unheard of level of security and possible make it the most high profile public implementation of smart contracts to date. Watch this space
Auto Save Enhancement
We currently auto save on page transition but for JavaScript clients we could do this on any change. Imagine a world were your browser behaves like IntelliJ and you never loose any data you type in.
Web 3.0 Semantic Web
Due to our data being so dynamic we may have the opportunity to go from web 2.0 to web 3.0 and again this could make this one of the first killer semantic web applications.