It's a little awkward, so we'll get straight to the point: This Thursday we humbly ask you to stick up for Wikipedia's independence. We depend on donations averaging about $16.36, but 99% of our readers don't give. If everyone reading this gave $2.75, we could keep Wikipedia thriving for years to come. The price of your Thursday coffee is all we need. When we made Wikipedia a non-profit, people warned us we'd regret it. But if Wikipedia became commercial, it would be a great loss to the world. Wikipedia is a place to learn, not a place for advertising. It unites all of us who love knowledge: contributors, readers and the donors who keep us thriving. The heart and soul of Wikipedia is a community of people working to bring you unlimited access to reliable, neutral information. Please take a minute to help us keep Wikipedia growing. Thank you.
Thinking of going the online course route? Then you might want to check out CoursePress. This plugin is easy to set up and allows you to create a full online course that site visitors can sign up for, complete assignments, take quizzes, and more. You have the option to create text, audio, or video-based courses, integrate discussion boards, and even offer video previews to entice potential students.
“[T]he stream of continuing payments that are earned by Brad and/or Karen from the commissions (current and future) earned by the brokers within a book of business. Residual income arises from all sources of income relating to or derived from an identified book of business, including commissions earned by the brokers within that identified book of business from any source whatsoever.”
Investing in coins and collectibles: Buffalo nickels and Spiderman comic books are good examples of coins and collectibles that can rise in value, and thus offer opportunity for passive income investors. You'll need to get up to speed on the value of any coin or collectible under consideration, but once you do so, you're on the way to price appreciation on a commodity you'll be paying a lower price to buy, and will garner a higher price when you sell.
People consider me an expert now, but I still have to get up and keep going in order to succeed and to provide value. You don’t actually have to be an expert, you just have to know more than the people who are looking for that information.  That was the case with Green Exam Academy. I wasn’t a person who got a perfect score on the exam, yet I was seen as an expert because I was the one talking about it online and I had done the test myself and passed it.
There is also an idea that we should work to build a passive income asset and then sit on the beach relaxing for the rest of our lives. The truth is that most people would get extremely bored with this scenario and will be eager to find something to do. That’s why the world’s billionaires continue to work… they love what they do and it stopped being about the money a long time ago.

Another benefit of residual income is that, if the income stream is large enough, one does not need the main focus of his life to be on making enough money to survive. Having a comfortable and continuous level of residual income opens up more opportunities to travel, look into other business opportunities, and even take the time to indulge in his hobbies.
PS Joel also throws up the whole coaching idea in this book, and whilst it’s not at all passive I just wanted to mention it, because this is one of the ways to create a six-figure business for yourself if you are a true expert in an arena.  ie you can use passive income info products (that generate say $30,000 a year) to pull in the customers for your 1-1 or mastermind style coaching service (that brings in say $100,000+ a year).