Advantages:
You learn things about current issues
You have fun
It's good family time- in moderation
Disadvnatages:
Huge cause in obesity because many people are glued, and can't stop watching TV. They never get out and excersice, and eat inordinate amounts of junk food without knowing it.
You can become antisocial social when watching too much
It can be a cause of major and minor behavior problems in children (i.e. grumpy, weepy, irritable, mad, argumentative)
You have limited amounts of time in a day, week, month year etc. Why not go and spend the valuable time doing more constructive things? Go bike with your family, hike, canoe, camp, read, play board games. TV is not your only answer to boredom. In fact, when one is glued, they probably will want to do nothing but watch TV. But, once they give themselves time restraints and limits on how much and what they watch, they will find out soon enough that there is plenty to do elsewhere.