"proprietary" is unfair, and becomes more unfair all the time now that Dart is on its way to ECMA standardization: http://news.cnet.com/8301-1001_3-57615494-92/google-convince...

If Dart is "proprietary," then so is asm.js, Mozilla Persona, Rust, and many other cool things that Mozilla is doing.

For example, take Persona. Mozilla invented, on its own, a new identity protocol which is not based on any existing standards and which it solely controls, released some code that implements it, and is trying to convince people to adopt it. When Google does the same kind of thing, it is called out as "proprietary."

> and open the door to Google services serving exclusively Dart content. Imagine if YouTube only supported Chrome.

This is exactly the kind of bad faith presumption that troubles me. Google is trying to push the web forward but in your mind their end game is to break its web properties for every browser except Chrome? This is so far from reality that I don't know how to respond to that, except to lament that distrust of Google by people associated with Mozilla is so high.