It is B+C =I
Simply translated for the non mathematical that means that Interest is a product of Benefits and Curiosity.
If anyone is going to be interested enough to read your website content or open your email you need to provoke curiosity and demonstrate some benefits.
So a headline for a college training restaurant that reads … XYZ college Restaurant Now Open Two Nights a Week .. offers no curiosity or benefits.
But say something like Tasty Local Seafood and Mystery Ingredient Being Served at XYZ College Restaurant provides benefits and provokes curiosity.
The benefits are the fact they serve tasty, local seafood .. local is always a draw these days. Tasty is preferred by all diners and seafood describes a wide range of possible dishes that lots of people enjoy. The addition of the mystery ingredient now piques the interest and encourages people to read on.