Lots of definitions and comparisons here. But: they all have some things in common:
1) There is a certain satisfaction of busting a moving target, it has a distinct difference from shooting a fixed target
2) Most trappers / skeeters / sporters are genuine enthusiasts who are more than willing to help someone who is new to the sport
3) You won't really know until you try it. Busting a clay in flight is kind of like learning to ride a bicycle. You can explain it all day long with the best technical writing skills and terminology... but, you have to give it a spin to really feel what is going on..
Ex - Navy, Persian Gulf Veteran. Loved shooting the M14, 1911, M60, M2