"A while ago, when .NetCF v1 wasn't released yet, we could only guess what kind of applications our customers would build. People on the team were coming up with various ideas of mobile applications they would like to build on top of our platform and try to figure out which platform features would be most valuable. We had application building days, when everyone on the team would go and work only on their personal application projects. ... We are bringing a subset of WCF (Windows Communication Foundation, formerly known as Indigo) to devices. WCF provides a new unified programming model for building connected applications with managed code. The cool thing I like the most about WCF is its' extensible channel architecture. It allows building applications that can work on top of completely different transports and protocol channel stacks. Using WCF programming model, now I can send and receive data in my application equally easily using HTTP, TCP or e-mail."
I have been trying hard to catch up on the Windows Communication Foundation on Windows Vista but now I will have to speed up the process because Windows Mobile will soon be getting a subset of the WCF. Check out this article by Roman Batoukov to understand how it works, how it will make the developers life easy, and the inspiration for this programming library.