As we all know, there are hundreds of ways that you can advertise your online business. With all the competition out there for customers, it is important to try to offer something extra that will make your business stand out from the rest. 
These kinds of "value-added" incentives come in all sizes and shapes: entries into a contest or sweepstakes, extra merchandise, travel incentives, and even cash rewards. However, there is one thing that you can offer to your customers that many people overlook -- your own expertise. What do I mean by this? 
Well, many people who come to your online business will be looking for ways to start their own enterprises (it's one of the hottest topics on the web). Since they have shown an interest in YOUR site, you must have done something right! Therefore, as an incentive to your customers, you can show them how THEY can have a compelling, successful business as well.
There are many ways you can pass along your knowledge to your customers: newsletters, advice sections, or even personal communication with your clients. One of the best ways to share your expertise with your customers, however, is to offer them free e-books (electronic books). These electronic books are easily constructed and distributed through your web site, and offer many distinct advantages. 
First, e-books have a long reach. If your book is well-written and/or especially entertaining or enlightening, then it will probably be seen by more than one user for each download -- it will be passed from one user to another. This means that you will be reaching many secondary audiences that ordinarily would not come in contact with you or your business.
Mark Joyner, CEO of Aesop.com, is credited to have started the whole e-book marketing craze way back in 1995 with his e-book titled, "Search Engine Tactics." The e-book was the first of this kind, was downloaded by over a million people, and was instrumental in the success and high visibility Mark enjoys today. "Search Engine Tactics is still the only ebook ever to get a 5-Star rating from ZDNet. 
Offering an e-book to your customers will also build your own credibility. By sharing your knowledge, you are proving to your customers that you have experience and expertise in that subject area. Most customers will realize that you are "teaching them everything they know, but not everything YOU know." By proving your competence, you engender trust and confidence in your customers. This can be more powerful than any advertising in the world.
So, if you are looking for a way to promote your online business, while bolstering your own credibility, consider using e-books as an incentive. They are inexpensive, compelling, and very powerful.