Two major new features to Emitter version 2.1 are composite behavior triggers and XML supports.
I've recorded some video tutorials to cover these features.
Also, I've recorded a tutorial on timeline-animated particles.
11 - Timeline-Animated Particles
12 - Composite Behavior Trigger
13 - XML
14 - More on XML
Alright, the total length of the video tutorials has reached an hour.
Probably I can name this playlist "Emitter in An Hour" :p