The particle tag works closely together with the particle systems. Whenever a particle system creates a new particle it calls the particle tag to initialize the particle. If the particle has no particle tag the default particle state will be used.
The particle tag can be used for various tasks like to determine how often a certain particle of a multiple particle system like on the image below is used or if the particles have a random size or position. Remember; turn off instantiation for simple particles, and leave it on for more complex polygon particles to improve render time.

Properties

• Frequency: If a particle system has more than one particle attached this property determines how often this particle will be use. Bigger values cause that this particle is used more often.
• Position: Adds a offset to the particle position.
• Position Variation: Adds a random offset to the particle position.
• Rotation: Adds a rotation to the particle.
• Rotation Variation: Adds a random rotation to the particle rotation.
• Scale: Scales the particle by scale.
• Scale Variation: Scales the particle randomly.
• Weight: Sets the weight of the particle.
• Color: Sets the color of the particle.
• Instantiate: Turn instancing on and off.