I remember seeing these images personally, but it's been a long time and I wasn't able to locate them again. Likelihood that any of these people would actually buy a plane ticket and pay her a visit? Pretty low. But is that a risk you really want to take, when you know they have your home address?
There's no need for "on the internet" to be different than any other part of life.
Simply walk to your local newspaper office and give a journalist the same treatment and see what happens next.
Or give a librarian at a public library a hard time exactly the same way.
Or just some random woman on the street.
We have extensive case law for "disturbing the peace" and all that kind of stuff.
This is not all that unusual. You can read about this kind of behavior and its consequences in your local police blotter, probably available online for free.
Regarding the harassment stories and Kathy Sierra, I think they took their trolling too far. I don't think they made specific direct threats on her life, but rather said things like "I wish XYZ happened to Kathy" and photoshopped up some tasteless images. I might be a bit hazy on it, since it was quite awhile ago.
I was a fan of Kathy's blogging, so I was bummed when she took her ball and went home. I still don't think they should have thrown the trolls in jail, unless they were making specific death threats towards her.