Microsoft says on Building Windows 8 blog that they are dropping plug-ins in Metro version of IE10 because the experience that they provide is “not a good match with Metro style browsing and the modern HTML5 web.” The company will continue to support Adobe Flash and other plug-ins on the desktop version of Internet Explorer 10. Metro is Microsoft’s name for the custom interface and touch layer for tablet devices built into Windows 8 .
“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,” said Dean Hachamovitch a IE team lead.