We're going to chalk this up to Mango-mania, but according to research firm Kantar, at least in Australia the HTC Mozart has been "performing well in the last 12 weeks".
While no exact figures were given, it's still interesting that such an increase was noted in the first place--especially since Android seems to be exploding there, now surpassing the iPhone. The HTC Mozart is a relatively old phone, being part of the generation 1 launch devices. Having said that, it's also one of the nicest in terms of design, featuring a solid, unibody case and a near perfect size for the pocket.
So why the sudden increase? Perhaps with the impending Mango update and all the news surrounding Windows Phone of late, including lots of positive reviews, consumers are finally taking notice.
Source: CNet Australia; Thanks, Dean, for the heads up!