It seems that google wants ,after having invested in gwt, go, and other stuff, to influence the web programming too ... The new baby is DART :
What is interesting to me, it's the people who have worked on it. Go was developped by C creator and fellows, and Dart by emminent Smalltalker :)
We may imagine that these two languages (go an dart) will share different kind of problematics and different kind of granularity, and not really compete themselves...
I imagine Dart like a Seaside-like language and framework with continuation inside :) We'll see that in few days.
I also suppose that dart is coming to replace java and dalvik on android machines, and this to avoid problems with Oracle. The path is long to make a new language successful, but if it is related to android, the success (like objective-C) may be guaranteed.