"Repackaging allows you to earn money multiple times on the same content. It’s a great way to grow your revenues without significant marginal cost.
Money One: A lot of our ideas originate on this blog. We post articles which generate traffic. We make money off the traffic by running Deck ads in the sidebar. We make a few thousand a month off The Deck ads.
Money Two: We bundled up the best blog posts about our software development philosophy and turned it into a PDF book called Getting Real. We sell the PDF for $19. We’ve made a few hundred thousand dollars from the PDF.
Money Three: We take the Getting Real PDF and turn it into a paperback at Lulu.com. We sell the paperback for $25 and we make a few thousand a month on royalties. The paperback is currently ranked the 4th best seller on Lulu.
Money Four: We took the content from Getting Real and produced a Getting Real conference series. We held a few conferences a year and made about $50K per conference. We’ve produced about 5 of these conferences."
from: http://www.37signals.com/svn/posts/1256-making-money-twice