Where do those software pirates get their illegal copies of installers?

just to satisfy my curiosity, does anyone here know how a software pirate can obtain their unauthorized copies of installers? it seems that before a new software could come up, they already have a copy of it. how do they get it on their computer? i don't buy them, by the way, i invest heavily on legal copies. but i tried to buy once and it worked well, updates and all. how did they do it?