Flash has not performed well on mobile devices. We have routinely asked Adobe to show us Flash performing well on a mobile device, any mobile device, for a few years now. We have never seen it;
and
Flash was created during the PC era — for PCs and mice. Flash is a successful business for Adobe, and we can understand why they want to push it beyond PCs. But the mobile era is about low power devices, touch interfaces and open web standards — all areas where Flash falls short.
—Steve Jobs in his Thoughts on Flash open letter about Apple's relationship with Adobe and the refusal to incorporate Flash into iPhone OS devices.
Q.E.D.
Update 1 Adobe's CEO: No, no, we are open, you are closed.
Update 2 Microsoft weighs in: Flash bad, HTML5 good. Jesus!