And I think all will be fine with Dart too. Today's release is very interesting for server-side development. In both cases, on the server and on the client side, people will use Dart when they prefer Dart to JS. And difference not only in syntax or amount of sugar, but in "how the whole system works" (don't know how to say it). And when you know that most profitable web project in human history is committed to Dart, then you can be sure, Dart is here to stay :)
Maybe because Rob Pike (one of Go authors) works at Google and many Google developers often write how they glad to write things in Go for Google needs. Next step is up to you - use search engines to get more information :)
Are they really committed to it though? The same way they were committed to Google Code? Google Glass? Google Video? Google Reader? Google+? All Google projects that they were "committed" to at one time. Now dead or basically abandoned.
Those are (closed-source) products though - Go and Dart are languages, and both are open source to boot - so if Google drops support, the open source community - and definitely the larger users that depend on it - can take over without a hitch.
Google Code is being dropped because nobody uses it anymore. Google Glass is on hold because nobody wants to use it and it's not ready yet. Google Video was dropped because they bought Youtube after realising they couldn't compete with them. Google Reader... I don't know, that was a bad decision on their part. Google+ was their biggest failure to date, I think, not because of a lack of effort on their part but because it never got the traction they wanted it to get.
Same as Google Wave really - too early, or nobody needed it, or something like that. At least they open sourced that project.
I think most if not all of the core team for Go are employed by Google, so if Google dropped Go it would have a huge impact. The community could pick it up but let's be honest, without the original backing by Google, the language would never have gained traction and would be just one of many interesting languages.
All those projects it dropped were consumer facing. These are programing languages being used inside google to increase productivity making a comparison between the two is a straw mans argument.
And I think all will be fine with Dart too. Today's release is very interesting for server-side development. In both cases, on the server and on the client side, people will use Dart when they prefer Dart to JS. And difference not only in syntax or amount of sugar, but in "how the whole system works" (don't know how to say it). And when you know that most profitable web project in human history is committed to Dart, then you can be sure, Dart is here to stay :)