In response to this article, which claims digg and stumbleupon are run by kids, this article refers to digg users as sophisticated.
I don't believe kids are sophisticated, or unsophisticated, they just have different patterns of behavior. Adults may be more apt to click on a link to buy some expensive electronics, because they have the money, where the youTube crowd is looking for entertainment. I use AdBlock, so I don't notice ads. Maybe more "kids" on digg use similar means of blocking ads. The content is what people want, pictures, videos, lastly text, about things they care about.
If kids don't click on ads, will there be more embedded advertising? Will every web video come complete with an ad? Will each flash game now have product placement?