Lately, I've been getting "We caught you watching porn and recorded it" e-mail scams.
They always use techno babble gibberish about how they are tracking you and put a virus on your computer to activate your webcam and record you.
Sometimes they reference you by name. One I received today called me by my name.
Sometimes you are lucky enough that they include your password.
All sites that I visit use identifying passwords. Something along the lines of /CastBoolits-1984. If I am lucky enough, they will include that. Sometimes I taunt them back telling them that they don't know my password so I don't believe them. If they give me an identifying password, then oftentimes I know which site was hacked.
So if you get an extortion e-mail, it is just because they hacked a site and got your information.
You can also check here to see if you were part of a security breach.
https://haveibeenpwned.com/