I never thought I'd find myself saying this, but...as one Facebook poster receives a short sharp prison sentence for a series of vile posts about April Jones and Madeline McCann, and another receives a community service sentence for Facebook offense, I find myself not entirely in disagreement with the magistrates.

Not entirely in agreement either. Because, let's say this at the outset, I don't think three months in prison for parading a sick sense of humour in public is the right answer. But nor is the facile reach for free speech as the ultimate get out of jail card. As a result of which I find myself outwardly in agreement with lawyer and blogger David Allen Green (aka "Jack of Kent"), when he tweets: "In a way it is more 'grossly offensive' for the criminal law to be used to give a 12 week custodial sentence to an idiot like #MatthewWoods". But scratch the surface and, I suspect, that he and I are now on wildly divergent paths over this free speech thingummy.

Let's start with where, I am guessing, we might yet agree. That is down at the end where free speech is OK - but yelling "Fire!" in a crowded theatre is not. The latter has long been recognised as a speech act, or speech with consequences. The fact that a bunch of people might get hurt, even killed, in the resulting pandemonium means the law does and should distinguish between speech which is about stuff and speech likely to make bad things happen. A similar distinction was drawn back in the early days of legislation around racist language. Speech that offended was to be deplored, but nonetheless remained lawful: that which incited to hatred - and action - needed to be within the remit of the law.

Somewhere up the other end, where I suspect I'd also still agree with David, is speech as pure idea. You should not, being Socrates, be condemned to death simply for discussing the merits of state governance. You should not even, appalling though I would consider the prospect, be criminalised for debating child abuse. As for explicit conversation between consenting adults, that, too, is no place for the law.

Where I begin to part from the old-fashioned 'free speech is the highest good' is when I consider the mundane chitchat that goes on all day, every day on social sites, blogs, Twitter and the like. People interacting with people: people expressing experience, telling of their lives, sharing, socialising and generally being good friends and communitarian. This is positive stuff: something I do over and above my regular journalism through my own blogs and random twitterings.

Only on more than one occasion over the last year I have downed tools for a while, overwhelmed by the sheer viciousness of people who take exception to me, to my politics and head over, sometimes en masse, to some space where I am engaged in debate to have a go. I must distinguish here. I don't object to intellectual challenge. I do dislike the vile, bullying stuff that is personally directed.

There isn't time in the day to lay out the full range of tactics. Though there are commonalities. People who KNOW my thoughts, my aims, my agenda on a matter, apparently better than I do. Disdain for anything that reeks of challenge: feminism, non-heteronormative sexuality, quirkiness. And a grinding, constant refusal to let anyone else express diverse opinion or to be last to post in a debate.

This is bad mannered. But its much more. An online friend and feminist blogger, Lorrie Hartshorn helped me, over a series of exchanges, to put this in perspective. We both value free expression. But we are also sick of being bullied out of our own virtual spaces just because someone else choses to shout over us. It's the online equivalent of someone wandering into our front room, drowning out anything we have to say by sticking fingers in their ears and intoning loudly and incessantly: "la-la-la".

A Father Jackian figure constantly interrupting conversation with a series of unconnected obscenities. Funny when carefully scripted and choreographed in comedy: simply annoying when its for real.

We wouldn't allow that to happen in our homes. We shouldn't allow it to happen online. Not least because, expanding the debate out to other bloggers, other friends, we found similar. People with interesting, insightful points of view drowned out, shouted down and eventually pushed offline by a certain sort of egocentric and insensitive poster.

It became clear that free speech, online is not some infinite resource - but can very much end up as zero sum game. Give it free rein, and expect a sort of unregulated speech market to form, within which the loudest quickly drown out everyone else.

It's more than that, though. When I looked at who was being bullied offline, it wasn't those with a voice. It was the usual suspects: individuals from minority groups, women, those just beginning to explore an LGBT identity, the vulnerable and those just beginning to find the confidence to assert themselves. As to who was being bullied, again a fair amount of usual suspectry: those with privilege, status, power, sometimes in society at large, sometimes within their own small community of admirers.

A recent advertising campaign by Expedia backing same-sex marriage has seen a backlash on Facebook and YouTube, with hundreds of posters putting up homophobic comment. Freedom of speech? For those commenting, perhaps. But as I dealt, only yesterday, with another individual in pieces, possibly even suicidal, as a result of online bullying, I don't think so.

In the end, a jail sentence for bad jokes is out of order - though those defending the perpetrator should factor in that his comments did stir up a mob and require police intervention, which shifts them squarely into the realms of speech act.

But free speech as trump card and excuse for every piece of online malice? No. The world is moving on. To be part of it today requires that we rely on freedom of speech to an extent never before imagined: and when one group's freedom is clearly limiting the freedom of another, it is time for the law to intervene.

Follow Jane Fae on Twitter: www.twitter.com/@JaneFae