Check out the: .NET Ajax Survey results
Simone has a great write up, including the raw data, I encourage you to check it out... But A couple of things that popped out to me:
1. Simone concludes that 84% of ASP.NET developers are using ASP.NET AJAX... That is an amazingly high percentage... I am excited that we could help that large a percentage of developers!
2. I am a bit surprised that only about ~50% of developers are using the AJAX Control Toolkit. I'd love to hear your thoughts on using the toolkit? Do you think it is a naming thing (people don't get the difference between ASP.NET AJAX and the AJAX toolkit?) or maybe it has to do with the heavy update panel usage, or are the factors that prevent developers from using the toolkit? Any theories?
3. Apparently, UpdatePanel kicks butt! 91.8% of ASP.NET AJAX users are using UpdatePanel. Personally, I love this feature as well. It gives you Ajax style of interactivity for your application without writing client side Ajax code!
4. Last but not least, I am absolutely amazed at the high early uptake of the ASP.NET MVC Framework. We are just a couple of weeks into our first public CTP and already 2.3% of folks said they are using it! That is way higher than i'd expect so early on. What is more, is that his a much higher percentage than any of the other, much more mature, MVC frameworks.