There are a lot of threads on porn sites
I know that in the industry some porn sites do take Bitcoins already not so sure about the escorts but it's far more common nowadays.
Look, I will give you just one example. Look at the mess with the Ashley Madison. Imagine if their users had an opportunity to pay in Bitcoin by staying anonymous or even semi-anonymous. I am sure many of them would choose this option.
Bitcoin can have many use cases like this one in the adult and porn industry, meeting and dating websites, etc. And I am sure it will have after the Ashley hack.
Ashley Madison is a good example of why you don't post your personal details when you are trying to commit adultery.