Microsoft has a representative on TC39 (Luke Hoban) who is extremely active. In fact, I usually find that my thoughts on some new feature closely align with his

Microsoft has a representative on TC39 (Luke Hoban) who is extremely active. In fact, I usually find that my thoughts on some new feature closely align with his. Because Microsoft has bet on JavaScript heavily for Windows 8 apps (at least for now), and Windows 8 apps have full support for ES5, they have very good insights about ES5. ES6 is still "coming". Many features are still in flux, and I don't blame Microsoft for not committing to in-flux ES6 features in the timeline of IE10.