I am sitting in the DevZone watching the Dreamforce ’11 keynote streaming live via the cloud. I’m exhausted, but incredibly excited. I wouldn’t have it any other way. Hey, it’s Dreamforce after all.

Yesterday, we opened the DevZone with an amazing turnout of folks checking out the Database.com, Heroku, Force.com, and Mobile App Dev zones. As in previous years, the workbooks—printed guides for getting hands on with the latest technology—are going fast. This year we have 10 workbooks ranging from Heroku for Java through to Mobile development in HTML5, Android and iOS.

Every year I have great conversations with developers on the show floor. The conversations typically revolve around how I can write my applications in the cloud. This year I have seen a subtle, but very important, change. Yes, the cloud is still front and center, but now it is really the enabler of the platform and provider of cloud-based services. Build an iOS app using the new Mobile SDK, push your Java app to Heroku, or power your HTML5 site rendered on an iPad. The Cloud is device-independent, your information enriched via Data.com and sourced from Radian6, and served securely from Database.com.

It’s a subtle change, but this is Platform as a Service.