Looking for an anti-ghosting keyboard?

Checking out this

keyboard, and I'm a little confused—what does "6-key anti-ghosting" actually mean?
Does it mean I can hit any six keys at once, or is it just limited to those red ones?

Anti-ghosting basically ensures your keyboard actually talks to your PC when you're smashing multiple keys at once, which keeps you from losing a match because of a hardware hiccup.

So does that mean any 6 keys will work?

Anti-ghosting is typically implemented on the W, A, S, and D keys, since those are the primary movement inputs used in almost every game.