I'd bet that 8-year olds (as a population), with their under-cooked brains and extremely limited autonomy have MUCH more predictable psych profiles and viewing habits than adults as a population.
Anecdote for illustration: I, and everybody I went to school with, watched the same show when we got home from school. How much more predictable a viewing pattern can you get? Plus, you can bet that I wanted whatever toy they were advertising, and bugged my parents about it as soon as I could.
Thinking about it, I'll never see data to confirm this but I'll bet childrens' TV advertisers have better conversion rates than Facebook, with all of its carefully mined and organized profiling data.