As a Netizen I feel obligated to know what Beeber, Harlem shake and Gangdam style is, however doesn't mean I like any of these.
Youtube nowadays could do more than most successful and deep pocketed produced a decade ago. Case in point - PSY - as an artist completely and totally unknown in 2011, gets to be invited to sing on one of hottest events - 2012-2013 Times Sq New Year party.
It's a sign of times. You don't have to like it, but Imo you have to know about them to be "in the loop"
I'm in my mid 30s and I listen to mostly classic rock, blues,soul, funk and many of sub-genres of these.