Email marketing
E-mail marketing, the digital evolution of direct mail, presents the opportunity to engage directly with the readers, at their own time and pace, and point out a situation/problem they are facing. A successful e-mail blast will show an understanding brand, sensible to the reader's situation, and then provide a solution in the form of helpful information and a product or service.
I've written hundreds of e-mail blasts, every single of them backed with research and a concept that singles out the problem to solve with the aid of a product or service.