Then one of my daughters started to get some very odd phone calls, from men asking for her by name, asking for sex. Wondering how much it cost. When they could meet.

She didn't go to pieces; children are so much more worldly these days. One afternoon, one of these callers rang my daughter when I was home. She asked him where he'd got her name and number. It was an online publication called Shaven Haven. As I write this, I've had a quick look and it doesn't seem to exist any more - although there are plenty of references to that phrase.

Eventually, we both managed to convince the operator of that website to remove her phone number. He admitted he knew of at least some listings that were pranks.

My daughter, then around 16, just dealt with it.

I googled that website one afternoon and discovered it was in the history of my computer's browser. The credit card details saved were not familiar to anyone in my house.

The young men who stayed in our house thought it was an amusing way to retaliate against a young woman who had rejected their advances. One of my teenage daughters had said no and this was a good way to seek revenge. From the computer in the house where she had said no.

You will have read about revenge porn over the last few weeks - the concept that, in order to retaliate against a person who has rejected advances or broken up a relationship, an aggrieved party posts intimate photos on the internet. Often those photos were taken in a consensual setting but that moment of consent is long past - and now someone wants revenge.

Sometimes the photos are posted with a contact number. Sometimes with an email address. But always with the real name so there is no mistaking who the person really is. Yes, it's just another chapter in the long guidebook on how to shame women on the internet.

But, even more seriously, it reveals just how little we have all developed when it comes to understanding what consent means. We are all so busy talking to our children - girls and boys - about sexual safety that we neglect the real need to talk about consent.

It is no longer enough, if it ever was, to just discuss sexually transmitted infections. It's not enough to say be careful when you are alone with someone you don't know very well. It's not enough to say be careful when you are alone with someone you do know well. Sexual consent is not one way - it is two people with equal power making a decision together. That is very hard to come by, even in the most stable of relationships.

And consent may not last forever. It's about interaction, intercourse and, more recently, the interchange of images that are a warm and intimate expression of the feeling felt at that moment. But love doesn't last forever and it usually doesn't come with the rider: ''Sure. I'm very happy for you to post nude photos of me online.''

We now need to recognise and accept that in every sexual interaction - and even in the stages leading up to sex - there is a serious prospect of misunderstanding what the other person means at that moment and into the future.

And I don't just mean what happens in the grip of the grasp. I mean what happens afterwards, when you have parted, as you flick through photos of somebody that you used to know very well.

The discussion of revenge porn - and of other online violence towards women - leads to a discussion of how to ban it. Which I'd love. I'm all for making it very hard for arseholes to make the lives of girls and women an online misery.

But, as Mark Pearson, professor of social media and journalism at Griffith University says, if we head towards a new tort of a serious invasion of privacy, we may find that those who are guilty of serious wrongdoing will use it to protect themselves. Pearson says while the Law Reform Commission recommended such a tort in 2008, it didn't develop a useful public-interest defence.

''We have no constitutional protection of free expression - a new tort would indeed address the situation, but it would need to be bolstered with a very solid free-communication defence,'' he says.

But that free communication wouldn't include posting the phone numbers and images of teenage girls, whose only ''crime'' was to say no.

Twitter @jennaprice or email jenna_p@bigpond.net.au