The purpose of this ad is to try and sell televisions by advertising it is good for family relationships, education, and keeping children proper. You can see this by the ads text but also the pictures of a "wholesome" looking family gathered around the television.
I think the target audience is meant for a Caucasian, upper middle class family, who wants to fit into the ideals of the 1950's. The text talks about tv making children smarter, keeping them in line "out of mother's hair", and spending quality time around a tv.
The genre seems to be 1950's tv ads. They do differ from today's ads because old ads try to appeal to the values of family and how good tv is. Today's ads are different because it tries to appeal to people's senses. Bigger, flatter, and high definition is what draws people in now.
The ad comes across as old school instructional propaganda. The tone it takes is upbeat and very matter-of-fact. It also tries to use "facts" in order to sell. The tone is meant to enforce the beliefs in a non aggressive manner.