Point - This will cause all particles to travel to a single point. Only the first three parameters have any function here. The particles generate according to the generation shapes above. The first parameter controls how far the particle will travel in the x-direction, the second controls how far it will travel in the y-direction, and the third controls how far it will travel in the z-direction. Each particle will travel at a velocity that will allow it to move that distance in one second. If the particle lifetime is set to less than one second, it will die before it travels that distance, and if the particle life is greater than one second, the particle will continue traveling in that direction at the same speed. Basically, the parameters correspond to the velocity of the particles in units persecond in their respective directions.
Box - This shape assigns a random velocity to the particles based on the parameters entered. The first and fourth parameters control the velocity in the x-direction, the second and fifth control the y-direction velocity, and the third and sixth control the z-direction velocity. For each of the directions, the velocity will be randomly chosen from within the bounds set. For instance, if your first and fourth parameters are -32 and 16, the velocity will be between -32 and 16. All numbers are in units per second, where each unit corresponds to one unit in Worldcraft.
Sphere - This shape has the same setup as the point shape for the first three parameters. The fourth and fifth parameter are used in this shape, however. Each of these two parameters has the effect of creating a sphere around the point. All particles will origniate at there generation point and travel to a random point somewhere between these two spheres. For instance, the parameters 32,32,32,32,16,0,0,0 will cause all particles to travel to a point somehwere within the sphere of radius 32 and outside the sphere of radius 16 both centered at a point 32 units in the x, y, and z direction away from the point of generation.
Blob - This shape also has the same setup as the point shape for the first three parameters. The fourth parameter is used in this shape. It has the effect of increasing the "spread" like the fourth and fifth parameter for the sphere. The difference is that this value has a much greater effect than the parameters for the sphere shape. Smaller values here will have a much more pronounced effect than smaller values for the sphere parameters.