The media often stereotypes people and races. Most children's programming deals in absolutes reinforcing the idea that people are good or bad, stupid or smart and because of their inexperience children will latch onto stereotypes that they see.
Parents can counteract this stereotyping by commenting when a group is portrayed inaccurately. Let your children know for example that every blond isn't stupid, and wearing black doesn't make you a bad guy. Point out that everyone has good and bad traits. So, often in the media a character is either good or bad, but in real life this is not the case.
The media uses its influence on children to market items and influence your child's desires making them think that they need certain items to be popular or cool. My children often comment on things that they saw in commercials. The other day my son told me that I should get a kitchen chopper, because it can cut things up so much faster than I can using a knife. I replied that I don't need a kitchen chopper because a knife works just fine.
Every year children influence their parents spending by convincing them to buy things that the media has portrayed as "cool". Children recognize name-brand products at an early age because they see them in the media. My children recognized the McDonalds sign by age three even though we never eat there, because they saw commercials on television.
Counteract the marketing by pointing out the faulty logic in commercials. Ask your child if they really think having the latest toy will make them more popular or happy. Children often don't realize that a Barbie won't move...