It's called SWM. 18-105 has SWM.
In Nikon, crop camera is called DX and full frame FX. Nikon DX lenses are compatible to both DX and FX cameras.
You should be more specific as DX lenses are not fully compatible with FX bodies. DX lenses can be used on FX bodies and works just fine but the image only falls on the center part of the FX sensor, so the usual crop factors still applies.
Similarly, FX lenses also works with DX bodies, the crop factor applies of course.
Not all dude. For some lenses you still can wing it... and still shoot in FX mode with DX lenses.
Example...
35/1.8 on D700.
http://www.flickr.com/groups/nikond700/discuss/72157622459065465/
Wow, I didn't know that but why is the 35mm 1.8 able to shoot in FX mode? Is the construction different from other DX lenses?
It's just that the projected image circle is large enough to be acceptable on FX...