To give a more practical example of the benefit to users of an open standard that browsers code to versus a proprietary plugin that a single vendor controls, I can point to the fine-grained control users have over javascript. Popup-blocking is now a standard feature for browsers, and most give users the option of controlling various other features which have been abused by web developers. The way this works is one browser will support the feature allowing users to limit javascript behavior, they start stealing marketshare from the others, and then the others are forced to adopt the capability to keep up. With proprietary browser plugins, however, the content is a black box handled entirely by the plugin runtime, over which the browser has little control. The user can customize what the plugin vendor says they can customize, and there is no drive to cater to users' needs instead of content partners, as all browsers must use the same implementation of the platform. Flash is all-or-nothing, and it's what Adobe wants it to be. Web standards are piecemeal, and they are whatever the user wants them to be.