While individuals may be insoluble puzzles, in the aggregate they become mathematical certainties.
When writing to sell your business to people, you can’t be sure how any one individual will react to your words. However, you can write so that the majority of your audience (and by audience I mean people who are possibly going to buy from you, rather than the entire global population) will react the way you want them to.
This means it is important to remember that one negative response is not the end of your business, and may not be representative of everyone’s reaction. It also means that you need to use words and expressions that many people will understand, not just ones that a few people will relate to.
Writing for a group will bring better results than writing for one or two individuals – although writing as if to individuals is still effective and personal.