(Namechanged as I don't normally comment on the sex threads...)
On pornography and erotica, people will have to draw their own lines in the sand but for me the clue is in the name.
Pornography is literally writing / media relating to prostitutes and erotica is writing / media relating to physical love.
The difference for me personally is in whether the people involved are both aroused and fully enjoying the sex for its own sake.
If they're faking pleasure for money as professional porn actors (or faking it because they're being coerced) it's pornography and I find it off-putting. The boobs are fake, the noises are fake, the juices are out of a bottle and don't even start me on depilated testicles - ugh! It's an entertainment media equivalent of poptarts or other unpleasant processed foodstuff.
Sexual media involving people who are both (or all) totally into the sex they're having is different. It's easiest to find in erotic fiction where some authors are skilled at depicting genuine sexual arousal and excitement. In principle, I suspect I'm enough of a voyeur to enjoy watching something where I honestly believed in the consent and full pleasure of everyone involved. Perhaps there are some films out there, made by people who are real exhibitionists and enjoying every minute, but I've never seen them.
Separately, I do also find calling women bitch / slut, humiliating them or simulating rape offensive and it seems to be prevalent in modern porn. As a teenager I saw a lot of porn due to a relative's profession (not what you might think - I had access to a warehouse of magazines of soft and hardcore variety and was of an age to find any sexual media fascinating) and the nastiness towards women does seem far greater these days for some reason. Then it was largely stupid but now it's nasty. I'm not an expert on the effects of participation in the sex industry but I can't watch this level of abuse of other human beings without feeling disgusted.
I read a lot and watched a fair bit of porn and spent too much time as an apologist when I was young and ignorant. As an adult I find most of what I've encountered dumb and misleading at best (no - whatever is done in the films generally isn't how to turn a real woman on) and offensive at worst. I do distinguish between porn and erotica.