Not everything could work as peer to peer (wikipedia as a mostly "plain old website" for instance), but many things could. Facebook and for that matter every we

Not everything could work as peer to peer (wikipedia as a mostly "plain old website" for instance), but many things could. Facebook and for that matter every web app who mostly acts upon data linked to an user account. Even backup/file hosting could work - but you have to commit a part of your bandwidth to provide service to other users, and bandwidth is limited by ISPs (there are probably good reasons for this tough). The approach could also be expanded in online games, tough we actually see things moving the other way around : maps you have to get from battle.net servers, ...