Things that change
...are more interesting than those that don't.
I've gotten about a dozen emails about Google's clever way of indicating that they keep adding storage to gmail.
Every time you visit your gmail account, you notice that the amount of storage you've been given goes up.
The same thing is true for the billboard on the bank near my house in Buffalo where I grew up. It didn't matter how many times we looked at it, we looked at it again when we drove by. Why?
In most organizations, the frequency at which consumers are sent messages is far greater than the speed at which the organization actually changes. As a result, most of the messages are boring and repetitive. Which means that you're training your prospects and consumers to ignore the messages--why bother reading something if you already know what it says?
The best stories change over time. They change in ways that fascinate the consumer, and more important, they change in ways that are fun or important to talk about.