It's been more thab two years since we first suspected the existence of an internal Microsoft project codenamed "Sparkle" that was intended to help designers build Longhorn user interface elements. Some suggested it was a "Flash-killer", but that didn't make sense - as Avalon was about a lot more than animations. Flash has matured considerably over that time, and has become a UI design tool in its own right.
Today's announcement has brought us a Sparkle that's very close to my initial speculations. It's a tool for designing rich Windows forms that separates the design task from development. Developers can produce template forms in their usual development tools, hand the form template over to a designer, and can carry on working with their code while designers build a rich user experience on top of the initial template. This is a new approach, but one that's not far from the interface-first design paradigm required by distributed application development. All we have to remember is that the user interface is important as our component interfaces - and needs to be treated in the same way. So design all your interfaces first, lock them down and then write your code (and your tests).
Looks like Microsoft has realised that it needs a complete set of design tools to get the Windows Vista application experience it's promised. Not so much an attack on Macromedia's market share, more a realisation that it'll need that class of tools to encourage designers to work in XAML. So we get Acrylic as a hybrid 2D/3d vector/bitmap design tool and Quartz as a web application design tool.
Of course the proof of the pudding will be in the eating, so I'll be waiting to get my hands on the code. I'll also e looking forward to applications that look a lot more interesting than the traditional forms metaphor...