The D600 is so new that many of the review sites haven't even managed to get a Review of it on line yet - Previews but not actual reviews. This is a very new camera model.
Then you have to remember that the Raw on every model of camera is different - and that's model not brand. So, the Raw from the D600 is different than the Raw from the D5000, the 5100, the 7000 and so on. So, Raw support has to be added for each model individually.
Then, you need to remember that Nikon and the other manfacturers don't share their Raw formats in advance, so the Software makers (like Apple and Adobe etc) have to get their hands on a camera, then reverse-engineer the Raw support from that.
So, taking those facts together, you see that there is a lag between the release of the camera and the Raw support being added to the OS.
Nikon is a major brand, the D600 is a major release from them so I'll happily bet that Raw support will be there for it, and probably quite soon. But if you're going to be an early-adopter of technology, then these things are a fact of life.
As for iWeb, well there are plenty of alternatives.
Regards
TD