You can get very different results depending on how you word a question. There is a whole science to it. To whit, the second option, "Pornography can exist, but certain types should be outlawed", saw a very small percentage of people pick as their response, yet if the same statement were reworded to say "Pornography can exist, but certain types, such as child pornography, should be outlawed" I believe it would have received the most votes.
To the question at hand, pornography involving consenting people of age should be a-ok in a free society. A free society should have a light approach to regulating morality. As long as children are not featured, as our society believes children are not developed enough to fully render consent, nor animals, which obviously cannot render consent in any verifiable way, then I am all for a free for all.
Now society does have an interest in regulating the production of pornography, i.e. mandatory testing of actors, in order to prevent the spread of sexually transmitted diseases. That, along with consent, is where regulation should end.