You probably know the drill by now, but if not it goes something like this. Every few months, new features are added to the Force.com platform. Every time we make such a release, you get a bunch of new stuff that you as a developer can use in your apps. We name these releases – and the next release is Winter ’11. For example, in the previous release (Spring ’10) you got Cookie support, push patch updates and Chatter!
The upcoming release preview webinars are where you learn about the new features coming down the line – where you can figure out how those features can help you in the apps that you build, or help you extend the apps you build. I hear, via the grapevine, that there may be an interesting feature to help you debug too. Register here.