Mac users can now take advantage of the fact that Mobile Safari in iOS doesn't support Flash in any way, by changing the desktop user agent. The problem is that even if a site offers up HTML5 video as an alternative to Flash, trying to get to it from Safari on a Mac will pop up the little blue LEGO block. As more people get fed up with the poor performance and security flaws of Adobe's Flash Player, they are uninstalling the Flash plug-in from their computers.