The extra chortle of recognition
When someone used to make a joke that referred to some pop-cultural ephemera - Joe Isuzu, or “Where’s the Beef?” or Zsa Zsa Gabor hitting a cop or whatever - we laughed because it acknowledged something we all knew about. When someone now makes a joke that references all but the most widely-known elements of web culture - business cat, “my parents are deaaaaad,” “Barack Obama is Your New Bicycle” - we laugh because we’re surprised that anyone else knew about that. It is a new level of laughter, the chortle of recognition: the simultaneous feelings of connection that things you saw by yourself were seen by others and disappointment that a thing you thought was particular to your social circle is actually widely known.
This, maybe, is the essential difference between mass and new media. TV fosters the illusion that we are all having the same experience, together. The web fosters the illusion that the experience you are having is utterly unique.