Depending on the browser, lots of things are already implemented, either generally available (e.g. `Promise`) or behind flags (e.g. fat arrows). This announcement just accelerates the adoption pipeline by reducing worry about spec changes.

I think it means we can now pine over EcmaScript 7.

It's underway already. Check out Kangax's amazing work here [0]

[0] ES6 COMPAT TABLE: https://kangax.github.io/compat-table/es6/