Porn msg identification?

[Richard D Alloway]

Hi there!

I was wondering if anyone had come up with a way to add a header or
perhaps prepend the subject line with something like {Porn?} based on the
language/content of an email?

I want to be able to give our users something they can filter their mail
against if they don't want to receive ANY adult messages.

Our customers like the ability to filter against {Spam?} in the subject
line for possible spam.

Thanks!

-Rich