Because television is so ubiquitous in the average American household it is uniquely placed to influence how people think and what values a society regards as most important. Television influences what people consume, how they conduct themselves socially, what they believe in, how they look and even how they act in relationships.
Yes, I do believe that television has a clear influence on society. Today it is rare to find someone that doesn't watch television regularly. When people watch television they are given ideas of what they should believe, how they should act and what their lives should look like. Commercials are a great example of how easily people are influenced.
People base expectations of their future on the people they see on television shows. People use the television as their news source, even if the sources are biased. Television shows present levels of moral standards that the society eventually adopts. Slightly racier shows are produces to draw attention, but ended up becoming the norm.
As an avid facebooker, I check the trending news feeds daily. Every day one of the top stories is related to what big television show just aired. Then come the memes and the kitschy t-shirts. Let's look at the Khardashians, who have built a huge empire on just allowing the world to look in on their lives. As a society, we are so very easily influenced.