Communication is critically important in all relationships at all times. If you don't communicate, you will create a point of failure.
How many businesses have closed down, and you hear people say, "I thought they went out of business years ago?" The business closed due to lack of customers. The customers stopped coming because there was no indication that the doors were open. Not communicating life, the business communicated that they were closed.
This communication is not limited to running TV, radio and news paper ads (for local businesses). For small, or local businesses, broken glass, damaged signage, chipped and pealing paint, darkened windows communicate decay, loss, "Sorry, We're Closed."
I was driving down east Second street a yesterday, and one of those old, rock buildings is getting a fresh coat of stucco on the front... a building I've never seen open for business. The old, plywood sign has been repainted or replaced with a new bright, easy to read sign. My thought was, "Cool. I'll have to check that out." I didn't even see the buildings around it or across the street, where I know the lights are on, but all look disheveled and tired.
Quarterly newsletters, post cards, an up to date web page, an electronic newsletter.... Just like a fresh coat of stucco, bright lights and clean windows, they communicate to your customers. They communicate, "We're open!" "We're vital!" "We're here for you!" "We want your business."