Winning a customer is expensive. Keeping one is where the profit is. Retention marketing is everything you do after the first sale: email newsletters, marketing automation, follow up sequences and the judgement to know when to send and when to stay quiet.

In this category we look at why people unsubscribe and how to earn a place in their inbox instead, where automation genuinely helps and where it puts people off, and how to make every message worth opening. Even our more unusual pieces, like optimising PDF files, come back to the same idea: respect your audience''s time and they will come back.

For businesses that already have a customer list, this is often the cheapest growth available.