Keep in mind that most of the stories that FOW relates involve a lot of re-starts. Flickr was originally a game, PayPal was originally a Palm app, etc. The key to persistence is to keep trying for the big-picture goal (becoming a successful entrepreneur); you don't want to keep flogging on an idea that isn't working out.

Of course, knowing when to quit is a skill that takes time and experience (with failure) to cultivate. In some ways, then, it's intriguing that setting an expiration date on your project might be the best strategy for overall success. Try everything for a year, and if it isn't working, try something else.