The ability to rapidly scale your application in response to changes in demand is one of the key benefits that Windows Azure delivers when you host your applications in the cloud. "If you rely on manual interventions to scale your application, you may not always achieve the optimal balance between costs and performance. An autoscaling solution reduces the amount of manual work involved in scaling an application dynamically."
In this video, we get to see how this can be accomplished with WASABi (the Windows Azure Application Block) in two different ways: either by preemptively adjusting the number of role instances based on a timetable, or reactively by adjusting the number of role instances in response to some metric that you can collect from your application or Windows Azure environment.
The first WASABi preview is available via NuGet (just search for 'wasabi' from the NuGet Package Manager within Microsoft Visual Studio).
If you want to jump straight to the demo, skip to 15:43: