Below I am going to go through three of the main particle spacewarps that come with max and explain what each one does. Of course wind can blow things around to simulate wind, but also it can be used to blow stuff up, and with negative values it can suck things up. Given the right decay values and the correct strength values it can be a really powerful tool for controlling particle systems. Gravity essentially I use for applying gravity to the scene, I rarely use it for more than that, applying this maybe with decay values can make objects drop to the ground ect. It works, and can be useful.
Motor basically turns things, very cool for making basic twisters.
A perfect example would be a twister, one or two systems for the main body of the twister, and one for the bottom layer of the particle system showing dirt spewing around the bottom of the twister, and perhaps one based for debris that travels around and through the whole twister. Another would be fire, with a smoke particle system emitting large billowing smoke as the fire burns away at something. Using particle systems togeather to complete tasks is a very powerful thing and makes things easier, so don't always think that one particle system has to do everything. Use fifty if you want to pull the effects you want off. So I think for the time being this will be the last chapter of smokin' but I will be writing plenty more on particles pretty damn soon.