@Oregonian: Particles are any kind of objects you want to release in large numbers which then follow rules you define. Let's say you want to animate burst of stars coming from magic wand (in an image). You define that the tip of magic wand is emitter, you want, say, 100 stars to burst in, say, 50 frames of animation, and then they should fly towards the borders (in random directions) of the image and vanish. You see this every day in TV, but of course those animations are done very realistically... You can do things like explosions, fire, smoke, water and many other effects with particles.
(*begin thinking again*)
Oh no. I did the math.

Particle system, to be useful, needs layers, masks and quite probably physics for emitters and magnets. In the end it is very close being full-fledged graphics editor. Which means it is quite insane to begin to write a new one.
Back to Blender, I guess. Somehow it always ends with "hey I can already do this with Gimp/Blender/Inkscape". Thank god we have these FOSS stalwart apps!
