Swift is a new object-oriented programming language for iOS and OS X development. Swift is modern, powerful, and easy to use.With no hint of open source, I suspect they truly mean "for iOS and OS X".
So, while it looks like a nice language, both in large things and small (though I don't agree with all their decisions), there's not much point in this language except for those already firmly in the Apple camp. This very nice system seems aimed squarely at making Apple developers more firmly just Apple developers.
And I distrust Apple as a corporation. Whatever prior art exists, I fear they'll have patents to dissuade 3rd-party implementations, unless they decide cooperation is in their business interests. Nice as it is, I guess I won't be touching it, unless Apple at some point makes a policy about being open with it.
Too bad. Though I do hope they prove me wrong sooner than later.
At least many other good options are already available.
(And on the topic of needing to be nice, I'm really just trying to say the issues that matter to me here. And I really would love Apple to prove me wrong.)