Metro style browsing and plug-in free HTML5
For the web to move forward and for consumers to get the most out of touch-first browsing, the Metro style browser in Windows 8 is as HTML5-only as possible, and plug-in free. The experience that plug-ins provide today is not a good match with Metro style browsing and the modern HTML5 web.
Running Metro style IE plug-in free improves battery life as well as security, reliability, and privacy for consumers. Plug-ins were important early on in the web’s history. But the web has come a long way since then with HTML5. Providing compatibility with legacy plug-in technologies would detract from, rather than improve, the consumer experience of browsing in the Metro style UI.
Microsoft makes the right choice here. Flash is not a good reason to buy a tablet or smartphone. Every single one of these devices that can currently run Flash do so at the expense of drastically reduced battery life and laggy performance. Not a good trade-off just to run a proprietary, legacy plug-in whose functionality can be achieved through other means.