I am not really into pornography, but in all technicality, it is a form of expression, and therefore it is protected under the first amendment. Naturally, if it hurts people, then it is not, i.e., Animal and child pornography. It's a touchy subject, but people have the option to stay away from this if they choose.
Yes it is, as long as it does not "hurt" others. If a person does not want to see it or believes it is morally wrong, then don't watch it or get involved with it. Teach your kids to stay away from it but you cannot make others suffer because of your religious views on the matter.
Porn is protected under the first amendment as free expression, both in its spirit and the judicial branch's interpretation. If the porn involves consenting individuals of age, then there is no victim involved, so there is no need to limit its expression. Porn may be similar to drug use in its spirit, but it's not bad enough to ban.
I do believe that pornography is a protected form of speech and expression, as long as everyone involved is a willing participant over the age of 18. The 1st amendment doesn't just protect the forms of speech that we like, but more importantly the ones that might be unpopular and quieted by the majority. So even though open display for pornography is taboo, it's existence is not a detriment to our society and should be protected as such.
Not that it's my opinion that pornography is necessarily good or bad, my main point is that it shouldn't be up to anyone to decide, and therefore should be allowed. What I may find offense or cross the line could be completely different than another American's opinion, and we all have rights under the First Amendment. The fact that pornography is prevalent, can be purchased in a multitude of stores and is everywhere on the Internet with no punishment to the people dispersing it goes to show that it is an acceptable practice. Larry Flynt, founder of Hustler magazine, went to the Supreme Court to defend his right to "free speech" under the First Amendment with his magazine, and I believe it was upheld. Whether you like it or not, it's every American's right to make, watch, read or write pornography if they so choose.