Dart is an unilateral project aiming to: "ultimate goal is to replace JavaScript", "rescue browsers from JavaScript" or "Google preps Dart to challenge JavaScript". Being open source here, is not good enough.
> Our main cost, running a live game, we managed to completely remove gets and puts and run in memcache. We hardly scratch our daily usage now.
Using memcache for store gameplay data is not the best idea. Memcache could be evicted at any time without any previous warning. Using a backend instance and storing the data in the ram is an order of magnitude faster, and thanks to the runtime environment api the service could stop gracefully.
So, I've thought for a long time ... if I could take a clean sheet of paper and write [a new language] that retains all the goodness of [JavaScript] ... I would not have come up with anything like Dart. - Douglas Crockford
I hope so