About: This post describes the differences between various versions of the .NET framework
There has been considerable confusion about the differences between various versions of the .NET framework. My colleague and good friend Carol Roy has put together this really nice picture that describes the various versions and the similarities and differences between them. As shown in this illustration .NET 2.0 and 3.0 share the same CLR version which means that all your .NET 2.0 applications will work fine in .NET 3.0 as well (unlike .NET 1.1 and .NET 2.0 where the CLR version changed)
.NET 3.0 = .NET 2.0 + WCF + WCS + WF + WPF
Checkout http://www.netfx3.com for more information about each of the four APIs that constite .NET 2.0
Using .NET 3.0 will greatly enhance productivity, reduces infrastructure plumbing and provides solutions in the areas of providing an identity meta-system, developing enterprise-class services, Work flow and the next generation UI.
Please note that with respect to .NET 3.5 all the usual disclaimers apply, the name will probably change and the composition might change as well, the interesting thing to note is that we plan to keep the same CLR version which means that your .NET 2.0 applications will continue to work. Please also note that our AJAX APIs do have the "Go Live" license already, I would encourage you to take a look at http://ajax.asp.net/ajaxtoolkit/ for an online demonstration of the various controls e.g. you can try the Accordian and DragPanel to have a tangible idea of how you can enhance your existing Web Sites or develop new ones.
<Click on the picture to view a larger size>