Here’s a quote from the late, great, Jim Young, one of the old masters of direct marketing. He said the purpose of advertising was to do 5 things:

To familiarise
To remind
To spread news
To overcome inertia
To add value not in the product

You could rephrase these:

To make people aware you exist
To remind people you exist
To give people a reason to care you exist
To let people take advantage of your existence
To tell people why your existence matters

Every bit of advertising you send out – hell, every communication – should be doing most or all of these. Next time you’re sending out a letter, or an e-mail, or a website update – ask yourself how it meets these five goals, and if it could meet them any better.