I have been a fan of Rich Internet Applications (RIA) for some time now. They give you much of the same functionality of a fat app but the flexibility of running them over the internet. There is no client side install and any computer with a compatible browser and an internet connection can access them. This architecture becomes extremely useful in organizations that have a decentralized workforce. There is no need to setup a VPN or open various ports on your firewall. They function over standard internet ports 80/443. They are much faster than running a data driven application over a VPN.

With such technologies as XML, Web Services and Ajax really taking shape RIAs seem to be positioned to soon overtake fat applications. Microsoft Dynamics CRM is a great example of a robust RIA.

With all that said, there seems to be big challenger to RIAs lingering in the horizon, Windows Server 2008 Terminal Services.

Windows Server 2008 is set to add many functional improvements to Windows’ Terminal Services. Terminal Services RemoteApp is one of the most impressive features in my opinion. Terminal Services RemoteApp gives you the ability to run a single application in terminal server. That means that you no longer have to share the entire desktop to end users. This functionality used with Terminal Service Web Access gives you much of the same flexibility as a RIA but the power of a fat app.

All in all, I am really comparing apples to oranges but I am interested to see how the battle of application development takes shape and if advances in Windows Terminal Services change the playing field.

I personally think RIAs are the way to go but I guess I am bias because I am a web developer but I am also a sys admin, so who knows.