Internet Etiquette...

I wonder what Internet Etiquette logic people use in their online behavior?

More specifically, I have questions.

1) Would you post a picture of someone on the net without their permission?
2) Would you post a link to a website without the website owner's permission?
3) Would you use the internet to post a humiliating story about someone?
4) Do you think you should maintain the same etiquette online as you do in your daily life?

To be fair, I have to answer those questions myself.
1) Yes, generally speaking, I think I would re-post an image of someone whose picture already existed on the net, but I would NOT post a picture of someone I knew. Even if they gave me permission, I would not post their picture. (Maybe I'll change my mind, but I need convincing.)
2) Yes, generally, I would post a link to a website without the website owner's permission.
3) NO, I would not use the internet to post a humiliating story about someone.
4) YES. I think it's important to maintain the same etiquette online as one maintains in their daily life.

Those are only my rigid opinions. I don't purport for one moment that I'm Mr. Right. I'm just curious about what other people think.