[hugh3]

I wonder what a better equivalent to such traditional means of the public showing disapproval would be online?

Easy. Write something. Put forward a rational, logical and coherent argument about why you disapprove of X, and publish it somewhere. Instead of just inconveniencing others with your temper tantrum, you might convince them to come around to your point of view.

One person with a sensible argument is far more powerful than a hundred thousand people with a poorly thought out chant.

[jrspruitt]

I've tried this many times in my life, and all I have found, is that there are people out there, who absolutely refuse to do anything about the problem. No matter how well the argument is laid out, how evil they have been acting, the only thing they will respond to, is force, because at that point, it is not up to them to change.