According to the annual survey conducted in September by Ajaxian.com, ASP.NET developers lagged behind other AJAX-enabled implementations. Surprisingly 50% of respondents were using PHP on their AJAX-enabled sites, with Java scoring 37%. .NET was third with 16%, placing it just two points about Rails.
Of course, a lot of things have changed since September. In the four months since then ASP.NET AJAX has become a mature product with the same drag-and-drop design that has made ASP.NET so popular. And with their open client-side library, non-ASP developers can also leverage much of the framework.
As mentioned in previous articles, this is also Microsoft's most serious attempt at entering the open source market. In addition to the framework itself, Microsoft is shipping a control library based heavily on community contributions.
Even more surprisingly, Microsoft has released its proprietary source code for the server-side controls as well. Under the restrictive Microsoft Reference License, developers can see how key functionality such as the UpdatePanel is built.
According to Gavin Clarke of The Register, we can expect even more in the next version of Visual Studio.
ASP.NET AJAX 1.0 can be used with Visual Studio 2005, and plans are afoot to support the next edition of Microsoft's integrated development environment, codenamed Orcas. Visual Studio Orcas will feature client-side JavaScript intellisense, JavaScript compilation checking, and rich JavaScript debugging for APS.NET AJAX.
As for the question, "Why the AJAX adoption rate is so slow for ASP.NET developers?", one theory is that developers are hesitant to adopt frameworks that Microsoft is expected to replace. For example, once Sandcastle was announced, virtually all effort on nDoc ceased. Now that ASP.NET AJAX is live, developers should feel more confident about picking it up without the fear of being stuck with a dead-end framework.