Security Impact of the Nokia/Microsoft Announcement

I am definitely looking forward to the collaboration Nokia/Microsoft and it seems to have gotten quite some chatter on the web. Interestingly, F-Secure looked into it as well: They looked at the app-model and the sandboxing technology in Windows Phone 7 and concluded (as we do as well) that malware on Windows Phone 7 is very unlikely. The strange statement was:

As a result, we don't expect any major mobile malware outbreaks just because of Nokia's partnership.

Maybe that I am just unable to see, how the risk landscape shifted but what has one to do with the other?

Nokia Windows Phone & Security

Roger