Of course he can't control his fans, but he still has them and that, by itself, is what makes the power relationship unbalanced.
I have to disagree with you there. It is only through influencing his fans that he has power, and in cases where he isn't influencing them then there is no power unbalance in his favor. I would think that at that site, at least originally, most of the influence would have been going the other way, until it got out of hand and spread beyond that venue. Who did the spreading, by the way? Is that known? Did he do it, or did she, or did other people bring it up elsewhere? And then, are the people who are attacking her so viciously
really his fans? I have to wonder about that unless he is the kind of person who incites his fans to behave that way. Maybe he is getting hate mail too, but isn't about to encourage it by acknowledging it.
What I do know is this: On the internet there is a lot of weird and unwholesome behavior. Not just in cases where people can act in anonymity, but even when they use their real names there are the geographic distances between them and the people with whom they interact, and that can make them feel safe about tossing around insults with people they will never meet face-to-face. Some of that behavior is highly co-dependent, and some of it is cruel and bullying. Once someone starts stirring up unnecessary drama -- and from what I saw on that site, it
was unnecessary, because it started out civil enough on both sides -- there will be people who automatically rush to their defense, just as there will be people who see an opportunity to make trouble and get out their poison pens.* And before long, it won't be the principals in the original disagreement who keep things going, or even just the well-meaning people who get sucked in for one reason or another, it will be all the people who were drawn to the drama and who feed on it. It would be impossible to estimate how much the people who feed on other people's drama (the trolls lurking in the shadows and writing anonymous letters) love, love,
love it, because they are not the ones being terrorized and they will never be held accountable.
That's why the internet can be a dangerous place, not because authors are trampling on their critics and wielding some great power they possess to crush anyone who says anything they don't like. Geez, if that were the case, authors would never feel the need to fight their own battles. They could just call in their slavering minions to do it for them.
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* Someone is going to say now that I'm blaming the victims, but I'm not. What I am saying is that people who have been using the internet for a while should know the dangers and not attract the attention of the trolls and the crazy people -- who will go on being crazy regardless, none of the people they persecute made them that way, but they'll be aiming it at somebody else.