As part of the OpenAJAX Alliance (which was just formed in February), Sun will work with over 30 other companies on ensuring tools interoperability, identifying best practices,and promoting wider AJAX adoption.
According to an InfoWorld article, Sun didn't initiallly join the alliance due to confusion about whether it was too Eclipse centric. ;) The trend towards the internet as an application platform (web 2.0) is definitely going mainstream with Sun and IBM backing Dojo, Google recently releasing the Google Web Toolkit, Yahoo's User Interface Library, the Rails community driving Scriptaculous/Prototype, Adobe's Spry framework, and others such as DWR and Mochikit.