Classic starcraft provided only a centralized chat server with game selection screen, and games were hosted on individual computers which created a game instance locally to which others connected by IP(exposing IPs to other player is really bad idea with current state of security). It was filled with tons of hacks, flooding, spam and abuse: IIRC there was even an exploit that dropped your client if you saw a specially named game in the game list. And since most people had crappy connections there was plenty of lag and player were often booted from games. This idea of spreading hosting to "other people" is misplaced trust and altruism. It only works in theory, with good networks and good people.