Three years ago, Daniel, my co-worker, showed me a book that was talking about developing Flash applications with web services together to provide dynamic graphic web applications. I developed an example and it worked pretty neat, but at that time I thought it was too cumbersome a process and forgot about it.
Now, using Pandora, I realize it's the first example of a website that did a great use of this technology meshup. It's the first time that I see a web application where using Flash makes all the difference in the user experience and it makes total sense. I assume they have webservices behind the scenes, although there could be a database direct access as well.
For me, three years and pandora and ajax later, I'm thinking on using Flash + web services to implement some areas of my next project, as it can give us the online flashy gamy look, it can give me the opportunity to accomplish completely independence of the design, and we can use GeneXus to easily generate the web services. It certainly would be much much less work (I need to find the flash counterpart that we can easily outsource in Uruguay) than implementing a similar, not so nice looking page in ajax ...
The one dis-advantage of this approach when comparing with the ajax approach is not being native in the browser as ajax is ... I'd think most users have the plug-in already installed.