Martin Lindstrom wrote an interesting book called Brandchild which he claims is "the world's largest study on kids and their relationship with brands." I found the following observation interesting:

When I conducted the research for my book, "BRANDchild", one result that surprised me was the number of channels kids are able to handle simultaneously. Adults are able to manage 1.7 media channels at the same time, say, watching TV and reading a magazine. Kids, however, can pay attention to an astounding 5.4 channels. They can watch TV, send SMS messages, surf the Net, chat on IM, listen to music, and even devote 0.4 of their simultaneous communications energy to homework.

I suppose this is further proof that mass-market audiences are a thing of the past. Television is changing, and so is advertising.