You can block someone, but that's too late, it's retroactive. If their goal was to insult you, mission accomplished, no obstacles.

In the case of Milo he'd encourage people to go and harass others which meant you'd spend hours and hours blocking people, they'd basically DDOS your Twitter account.

Is this acceptable behaviour? Is this something to be encouraged by not punishing it?

I don't think you realize what a lightning rod some people become through no fault of their own. That you've never been struck is simply a matter of luck or not being one of the common target groups.

Remember: Not having a Twitter account doesn't mean you can't express yourself. You didn't get kicked off the internet. You're not barred from making sites or publishing your thoughts on innumerable other places.

Yes. They should fix that (if these recent changes haven't yet done that). I've had one of the worst mornings of my life in the last year when I criticised a new browser API and the author of the API refused to stop mentioning me for an hour despite being asked repeatedly to stop. Having to turn off your phone because a high profile person is angry at you is awful. Having people threaten you or publish your contact details is much worse.

Who draws the line between criticising someone and 'pushing others to harass'? Would you block people on the left who have criticised people on the right who were subsequently harassed? Milo had syringes sent to his house and his mobile number published, Totalbiscuit and his wife received a bunch of death threats. We shouldn't ban all the people who criticised them because they were subsequently harassed - I'm sure you wouldn't support that and I'd be right there with you. We should ban people who actually make credible threats, publish non-Twitter contact info on Twitter as a way of harassing others, and similar behaviour.

> Not having a Twitter account doesn't mean you can't express yourself.

Yes, just that you can't express yourself on one of the few places for discussion, and more to the point, that other people who want to hear you (and in Milo's case that was a lot of people) can't do so.

> You're not barred from making sites or publishing your thoughts on innumerable other places.

But due to Metcalfe's law none of those other places have any worth.

As one of the grandparent comments says, we don't trust the free market to protect other values, we shouldn't trust it to protect freedom of expression.