This article: http://css.dzone.com/news/google-dart-%E2%80%9Cultimately very nicely says the following:

– that a group of really smart programming folk are making a computing language for client-side processing called “Dart” to compete with or follow, or take the next steps in web development where JavaScript falls short.

– That the process to do this will lead eventually to an open and free language, but that all the core initial development of the language will be done within Google (or with all Google people to be more accurate)

– That this is a political and perilous process of reasons too complex to rewrite here, but includes getting the creator of JavaScript on board while also calling his baby essentially “deeply flawed” (my quotes).

– That another major hurdle is getting the browsers on board.