I think one reason why Oliver enjoys so much success is the fact that HBO posts the main news story section on Youtube after every show. The ready availability

I think one reason why Oliver enjoys so much success is the fact that HBO posts the main news story section on Youtube after every show. The ready availability of these digestible segments helps extend the show's reach. For Comedy Central shows, if you don't watch the episodes on TV you have to use the Comedy Central website or Hulu, neither of which have the appeal of Youtube. I like Oliver, but Colbert is (was?) still my favorite. I didn't watch him for the news, I watched him for the comedy. I don't think either Stewart or Oliver can match Colbert when it comes to being really really funny.