Your e-book can literally be viewed by millions simply by giving it away for free. You can make your site remembered and more popular by giving away electronic publications. You can also give the recipients a permission to distribute your book freely among their own subscribers, visitors, affiliates and clients. Visitors remember you for a long time for offering valuable knowledge. You may also add a banner advertisement into you e-book which connects the reader directly to your web site.
Possibilities are endless.
Promotion - provide valuable information on a specific subject to bring traffic to your site. Manual - you can instruct you customers using an electronic training manual. Electronic books - writers can offer their books in electronic version. Possibilities are endless. Consider this concept.