Imagine there is a circus coming to town and you are seeking to find ways to promote the event and encourage people to take advantage of it.

ADVERTISING: You paint a sign that indicates the time and location of the circus.
PROMOTION: You place the sign you made on a circus elephant and walk the pacaderm through town.
PUBLICITY: This is what happens should the elephant walk through the Mayor's flowerbeds.
PUBLIC RELATIONS: When the Mayor laughs about the mishap.
SALES: The town's citizens go the circus, you show them the many entertainment booths, explain how much fun they'll have spending money at the booths, answer their questions and ultimately, they spend a lot at the circus.

When the above principle is applied to the use of a business forum it might look like this.

ADVERTISE: You send targeted emails and use press releases to announce the launch and location of your forum.
PROMOTION: You find a supplier or business associates willing to provide details about your forum to like-minded customers.
PUBLICITY: This could be a post either negative or positive that ultimately is used to draw guests to your forum.
PUBLIC RELATIONS: When competitors recognize your forum as beneficial and try to downplay your success.
SALES: Citizens of the World Wide Web come to your forum, discover the educational and community aspects of the forum, read about products you have for sale, have their questions answered, and ultimately purchase one of your products or services.

People don't want to be "marketed TO"; they want to be "communicated WITH." - Flint McGlaughlin

The use of a forum board allows a natural progression for your customers. You can track customer trends and reasoning and they are allowed the freedom to communicate in a way that traditional marketing campaigns have never before been able to provide.

A forum may likely take on a life of it's own and require little personal involvement from the business owner. While this may be good news it is in your best interest to check up on the forum from time to time if only to get a feel for the tastes and trends of your customers. After all, when you get right down to it, that's the information you need anyway.