Yes, that is true if you use a particular email address to sign up for the porn site, then you will for sure get porn advertisements and promotions sent to that email address; you may or may not get spam like the email in question which is slightly different imo.
I get misc porn spam sent to my yahoo email even though I have not used it for anything porn related.
Also, in my experience, once they have your email address and you start getting porn spam you will get it forever, especially in your spam folder. However a person can unsubscribe to legit subscription sites that they may have given their email address to in the past.
They definitely target advertisements to specific people. Regardless, this thread makes me think that I should permanently discontinue using my old yahoo email address, it really is the worst email service, google is far superior.