There has been studies done that show that porn has the same effect on your brain that illegal drugs do. It is an addiction, even if you don't know it. If you view it regularily, and don't think that you have an addiction, try going without it for a week or month, and it will most likely be harder than you thought.
However, many people don't have a problem with being addicted to it, or they aren't addicted and take pleasure in it, but could stop whenever they wanted.
I think that if you want to view porn, it should be available, but not in public where kids could see it, because they don't know what they are seeing, and are way too young to be thinking about sex. One of the laws where I live, Alberta Canada, is that alcohol cannot be sold in the same public grocery stores. So places like Safeway usually have a liquor store around the side. I think that pornography should be the same way, so that kids or those who don't want to see it don't have to, but yet at the same time, it is available for those who want it. I know that some people might think that it is unfair that you have to go to a different place, or are being set apart from people who don't view porn, so you are not being treated equally, but this is only my personal opinion.