if you google DOF which means Depth Of Field the first or second link will give you already a wikipedia entry. to spare you the heavy typing, it is a photographic term describing how much field you have till it starts blurring out. it is simulated in 3d to make blurry for-, backgrounds.
Bongo is McNeels own Animation package, a homegrown plug in.
If you have both at hand C4D or Blender, i would prefer C4D because i am used to it. The interface is known to be very intuitive and the package is very capable. Blender is a very powerfull tool which is getting a lot of attention these days not only because its free but also because the development is constantly being pushed and has evolved into a very serious “competitor” even for commercial screening. but the interface was never a real friend of mine. i tried many times to get into it, even they changed a lot to make it more inviting for the masses, but it remains akward.