1 word: 134% more traffic but 26% less sales

Neil Patel ran an interesting experiment by using a certain type of word in a headline for his emails and a blog post.

As a result, he got 134% more traffic but the income dropped by 26% (+ more unsubscribes and more negative feedback).

You’ve also probably thought of using this word at least once in your life.

What was this type of word?

This type of word was a swear word.