Don't get me wrong, I love Unity. I think it's a great engine. But surely we should refer people along to Unity's official QA website? That's a better place for their questions (even if it is terribly built compared to SE).
I think Unity questions are fine.
Unity Answers isn't part of the StackExchange network. We don't close questions on UDK, Ogre, or OpenGL, or Direct3D (et cetera) with a link to the appropriate support site or forums for the technology -- there's no reason to do to so unilaterally for Unity questions just because Unity's official support site is a StackExchange look-alike.
Maybe I'm biased (I am), but the moderation here is a lot better than the moderation over there.
I, for one, welcome good Unity questions. If the questions help drive traffic to our site, they're on topic, and they "help make the internet a better place", all the better.
On Unity Answers you often have people that don't know how to handle the QA-system correctly.
Often people ask only one question and then disappear.
You get a lof of questions there, that could be answered with a look at the manual/reference.
For my part I'ts nice to know I could post a question here and might get an answer from someone that has a broader horizon (a not ONLY Unity user).
Unity questions belong on UnityAnswers or the Unity Forums. I think wherever possible, technology-specific questions should be asked on fora dedicated to that technology, so as to contribute to those individual resources. XNA to its own, Unity to its own, iPhone dev to its own, etc. etc.
The only time users should really opt for this site over those sites is when the question tends more toward technology-agnostic games or simulation-related problem-solving. The best questions on this site, and the best answers, rarely have to do with individual technologies, IMO.
Wouldn't you rather have one single go-to point for a technology you are learning about, than to have to hunt high and low on the web (much fun as that might seem)?