Meaningless, except for those "in the know". It means, literally, that someone on this planet or somewhere in the universe, is also listening to the same exact song you're listening to right now, beginning and ending at the same time, simultaneously, whenever you listen to music. A mockery of all the ___-core buzzwords used to hype this or that new band. In short, no one is as special as they'd like to think they are.
OMFG, I love Dick Wang and the Johnsons, they are the sickest simul-core band there is!
by scarebear April 27, 2006