Spammers get more response from smutty emails than any other form of junk email.

While penis pill offers and pharmacy drugs continue to bring in a small percentage of punters, as many as one in 20 recipients visit porno websites after receiving lewd come-ons by email. Response rates for pharmacy drugs (0.02 per cent) and “Rolex watch offers (0.0075 per cent) are miniscule by comparison, according to a study by email filtering firm CipherTrust. The sales to click-through ratio for pharmacy drugs is one to 150.

Read more: We’ll buy smut if you send us the spam