Some interesting numbers out from Nielsen today showing how as people age, their consumption of TV changes, the money quote from the piece "[Y]oung people’s media usage is markedly different from that of older generations but is likely to converge with their elders as they themselves grow older"
The teens of 2001 watched less than 25 hours of television a week but by 2009 as they aged into 18-24s, they were watching 31 hours of television. Even more dramatically, the young adults of 2001 watched less than 25 hours of television but watched more than 36 hours a week of television as they aged into the 25-35 cohort.
via Nielsen Wire. Lots more explanation of the likely reasons for the changes there.
Here's the chart showing the changes in TV viewing patterns as those groups aged: