DD selling her body online

I disagree with some of the others here about friends. Friends are always a huge part of what teenagers do. If they thought it was uncool, she wouldn't consider it. It may be her decision, but in that context.

Untrue. I had a couple of friends who did similar work 30 years ago when I was young (magazines rather than online). I don't know any of their friends that thought it was 'cool'. They did have abusive fathers though.

They came through it to have professional careers, one works with children.

I'd focus more on her future. What does she actually want and how can she achieve it?

I'd just point out that anyone can take a screenshot or onscreen recording (using Game Bar on windows, for example) and hold that for posterity. And that if such a video surfaces later on, it may ruin her chosen career, depending on what that turns out to be. And she may change her mind about her preferred career later on.

How utterly awful. Tea and and and sympathy.

I disagree with some of the others here about friends. Friends are always a huge part of what teenagers do. If they thought it was uncool, she wouldn't consider it. It may be her decision, but in that context.

And I disagree with you that you've failed as a mother! Parenting is only some of what kids absorb. There's a whole world out there bending them every which way. Keeping them away from it only makes for really weird kids, as you see in some cults.

I'd think the worst practical effect, aside from the increased risk of bad experiences in the present, is all the opportunities it shuts out in the future, given that the internet is forever. She's obviously not thinking about that, but if there was some way to help her take it on board, it'd be worth doing.

Anyway. I wish there was some real help I could provide!

You haven't failed as a mother. But honestly, if you try and dissuade her you risk making her carry on without telling you, and potentially stopping her from confiding you in the future when she really needs you.

Realistically all you can do is ensure that she is staying safe and being practical. For example there is potential for ex clients down the line to recognise her, does she know how that will effect her in terms of jobs etc. Does she have a plan for if anyone attempts to use the video footage for nefarious means, such as shaming in uni or the workplace or worst case scenario blackmail. Is she ensuring that her identity is as secure as possible?

Not that it matters I suppose, but has she said what kind of videos she is making? A girl I went to uni with used to sell pictures and videos of her feet online. She felt secure and safe in the knowledge that feet are feet and it would be impossible for anyone to know it was her, so wouldn't have any risks of identification down the road.

Great advice from TBHno, just to add many women have done short term work such as this and managed to come out the other side unscathed, and if anything far more educated about men!
It’s great she’s told you, perhaps because she wants the support to leave this behind her.
Remember she’s still your baby girl inside ❤️

There’s not really anything you can do. If she told you, I imagine she was either looking for support or to shock you. I would just let her know you don’t really approve because it isn’t what you wanted for her, but you are here if she needs anything.

I do think you can’t really blame her friends’ influence though. At nineteen years old this is her decision and I don’t think it’s helpful to blame other people. It must be awful for you though, hope you are okay.

I wouldn't bamboozle her with the negatives. I would try to take a more balanced approach in order to guide her in the right direction.

For example, you could try to get her to write down the pros and cons of such work? Once written, she may come to the conclusion that there are far more negatives to positives with this kind of work.

You could also gently ask her how she may feel about this when she's 40, 50, 60, when she will probably be in a different career? How would she feel if her future work colleagues found out? Is she happy to keep switching careers every few years? As this may well haunt her.

woofwoof not really helpful.
OP I feel your pain. Ask her what she'd do if a relative - father/ brother/ cousin or someone she knows discovers her site?
Maybe she hasn't really thought it through.
Come up with some tangible other means for her to make some money. Good luck.

I think it takes a lot more than encouragement from friends at uni to make a women sell her body online.