Safari on Windows - What's that all about then?

Surprise announcement today on the Beeb got my attention.  Immediate thought - what the heck are Apple up to here?  My current best guess is that it is designed to shift Apple Mac hardware.  Maybe the reasoning goes like this:

We have millions of happy ipod & itunes users on Windows.  Let's capitalise on the positive feelings towards the Apple brand to give those consumers another way to be cooler than their friends.  And since most consumers spend, what 90% of their time in the browser(*), next time they come to upgrade their computer why would they choose a Windows PC?  Anyone have any other theories?

(*) and most of the rest of the time is likely spent in two other applications that both run on Macs - Microsoft Office and Adobe Photoshop CS.