This has been beaten to death on HN repeatedly, so searching for previous Dart articles will tell you a lot. To sum it up, right now it compiles to JS, but it

This has been beaten to death on HN repeatedly, so searching for previous Dart articles will tell you a lot. To sum it up, right now it compiles to JS, but it could eventually be integrated into Chrome proper, and eventually other browsers. The latter is unlikely for the short/mid-term, but may never happen at all. Subjectively, it's a boring (which isn't a bad thing at all) but very productive stack. The optional static types are nice, and I like having so many batteries included. The syntax will be somewhat familiar to anyone using C#/Java/C++/Python. It most resembles C# to me.