Like Apple with iOS for iPhone and iPad, Microsoft appears to have no intention of supporting Adobe Flash or other web plugins in the upcoming IE 10 for Metro in Windows 8 tablets.
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.