It's custom.. lots of separate simple shape comps built up then animated. no plexus except for MAYBE the part with the "thousand no's for every yes" but that's pretty bare minimum usage. Could also have just been a 3d program with matte renders.
It's funny, I've had 2 clients reference this when in break-out meetings talking about the style they want for their project.
I wouldn't outright mimic it, but try your own thing on black and white with minimal lines and dots, etc.. should be fun!
On a side note.. I wasn't too enthused by this piece when I saw it.. I mean, the work is nice and it's minimal, it just feels like it was supposed to build up better and it never really impacts me the way I expect it to.
It was designed by Buck (
www.buck.tv) They've got a TON of awesome work on their site.