As someone who has recently passed the early teens and is now 17 I can say that there is not that many problems with the signs your son is showing. I first became aware of porn first year of high school, as everyone had it on their phones and sent it around. I also have done a few things with matches and deodorant that I probably shouldn't have, but we generally grew out of it. I do find that friends play a big part in what you do as a teenager, my group of friends pretty much went through the same crazes all at the same time. I have never ever tried a smoke, and only now do i drink, and lightly at that. I guess what my parents (esp my dad) did for me is never discipline me harshly, they explained why when I did get in trouble, but most importantly I had huge respect for them. Dad used to take me to the cricket nets and we had the biggest rivalry ever going on. I now go golfing with dad, and I really enjoy his company.
From a reasonably young age I was around dad's friends. They wouldn't let me drink but they respected me, included me, and I felt really special having adult friends. I respected them as well. I guess if you accepted your son into your group of friends like my dad did, he can mature a lot easier, and 5 people telling you something is much more powerful than one. He can also feel a lot easier around alcohol, smokes (if any of your friends do so) and general talk that all lads have.
Smoking is the biggest problem, and I feel that is down to the friends he has, not your parenting. At school there are groups that are friends, and coincidently, they all smoke. Its all about self confidence for your son to resist peer pressure. I chose not to drink when I was younger and I am proud of that decision now.
In my opinion you just need to be a good role model for your son, but also explain what you were like when you were younger. He is much more likely to listen to you when you tell him of your stories from a young age rather than preaching to him about how you never ever thought about banging any women, drank anything but water or stayed out past 5pm until you were 18, because then he will know that you have experienced the true life of most teenagers. He will also feel much more connected to you than he would otherwise.