If you've written newsletters for a while in the traditional "news" style, you'll know how frustrating it can be continually having to remind people what you do as you get new subscribers. In your first issue, full of enthusiasm, you might have told your readers that they can get a discount or sign up to another of your great services. But as the numbers grow, perhaps thousands of people have missed some crucial or brilliant piece of advice you wrote a year ago while you're always struggling to come up with something new.