One of the things that is a constant worry for parents is TV viewing, about how addicted their children are to TV, about how what they view affects them and about how it keeps them from engaging in other healthier, more physical activities.
So it is imperative that parents are cognizant with what their children are watching and have an appropriate measure or control over it. And there are several ways to do so:
To the end that parents would have more control over what their children watch by law, all TV sets manufactured after the year 2000 were required to be manufactured with a V-chip.
This is something that helps parents block certain channels that are unsuitable for children to view. This V chip also is able to gather data about the rating of the shows on TV. It receives information about TV Parental guidelines.
These are important for parents to know and understand: These appear for several seconds at the start of each show. TV-Y for instance means for all children.
Then it gets progressively different for children of all ages: for 7 and older, programs where parental guidance is suggested, and parents are strongly cautioned and so on.
A complete list of these guidelines and ratings are given here, which parents should make themselves aware of, so that they can effectively make use of the technology they have at their disposal.