I know that the get color from layer option was used here.
I assume that the logo was masked out with a blocker over time so that it wiped away the logo. The get color and transparecy from layer option are explaned in the help files in depth, but the gist of it is, that you can put an emitter over a BG picture, and have an emitter take it's color and transparency from that layer - so that particles are only emitted over an area where there is smething in the image.
It's 2 pI3 project files and the pI logo image. The "fill in" project creates particles at the logo and they rise up, so after rendering the frames need to be reversed (I did it in After Effects, but there are many other ways to do it). The "fill out" project doesn't need this done to it.
The last part of the clip (the wondertouch logo flying together from a circle) uses one of the existing emitters in the "logo effects" library available on our downloads page. I just replaced the shape (image) for the particles.