– The Curve Guide is used to force particles to follow a certain path defined by a Curve Object.
– You can also use Curve Guide to shape certain hair strands.
– You can also use the Particle Edit Mode to define a path.
– The option Curve Follow does not work for particles. Instead you have to set Angular Velocity (Particle system tab) to Spin and leave the rotation constant (i.e. do not turn on Dynamic).
– Curve Guides affect all particles on the same layer, independently from their distance to the curve. If you have several guides in a layer, their fields add up to each other (the way you may have learned it in your physics course). But you can limit their influence radius by changing there Minimum Distance (see sub-menu).