Would you keep your nicely designed business card for yourself? No, probably not. Your goal is to get it eyeballed as much as possible.
Within a day, there were 30,000 downloads from my site (and those downloaders were in turn free to make more copies). Three years and six printings later, more than 700,000 copies of the book have been downloaded from my site. The book's been translated into more languages than I can keep track of, key concepts from it have been adopted for software projects and there are two competing fan audio adaptations online.Yes, he could be losing a few sales. But as Cory so poignantly reminds us, the people who are downloading the book wouldn't have bought the book anyway; you're simply building a larger audience and enticing some others to buy the hard copy. There's a parallel to music here, musicians have long been giving away their stuff on blogs and MySpace. As a consumer, if I get a free taste of something, I'm more likely to buy something. I may just become a lifelong fan. And I may just attend a concert or two or ten. Concerts, like speaking and consulting gigs, are where musicians make their money. Giving your idea away (granted it must be good) will make people hungry to experience your ideas in other spots. Don't keep it for yourself. Share the love.