You brought some awesome examples. One of the best ways to get your campaign off the ground is by starting with the ideal audience. I find that I can use data to find my top customers and then make those into ambassadors, nurture those relationships, to create an epic viral campaign. Gilles de Clerck, founder of the Growth Revolution, talks about it here -

Writing an e-book is very popular among bloggers, as many have noted that “it's just a bunch of blog posts put together!” You will not only have to make an investment of time and energy to create the e-book, but market it correctly. However, if marketed correctly (through blogging affiliates in your niche, for example), you could have residual sales that last a very long time.
While compiling this list, I did my best to avoid scams, and stick with practical ideas that work. I have tried many (but not all) of these ideas. Some of these helped me earned a few dollars here and there, but there are some that helped me earn extra money on the side every single day — and some are still providing me with revenue! Note that not all ideas will fit your skills and abilities. What works for you depends on your abilities and your current financial situation.
I've got a $185,000 CD generating 3% interest coming due. Although the return is low, it's guaranteed. The CD gave me the confidence to invest more aggressively in risk over the years. My online interest income has come down since I aggressively deployed some capital at the beginning of the year and again during the February market correction. You'll see these figures in my quarterly investment-income update.

Can you expound on the use of publicly-traded REITs as a passive income source? I’m 31 years old. No children. No wife. No dependents. (I am the closest thing to Ebenezer Scrooge you’ll ever see). My monthly expenses amount to less than $2,000 per month (most of which go to pay student loans) . I have a decent job making over $55K per year. I also have a $60K inheritance coming my way in a few weeks. I am absolutely crazy about achieving absolute financial independence, which for me would require a passive income of over $2000/month to cover my living expenses. I could achieve that in a mere couple of years if I were to save excessively and dump my savings (and inheritance) into a Mortgage REIT via the stock market, most of which are shelling out above 10% returns in dividend payments. Is this a good strategy for me? Or am I being too hasty and assuming too much risk?
Thank for this extensive work. When you make extra money you need to think simple. First thing you should consider is whatever you do must be safe enough that you don’t lose your initial investment as well. Also, look at the ways you can reduce your costs. This could be car insurance savings or paying back expensive loans or card balances. Saving is making money as well.
Scales easily from small to very large. To spread like wildfire, the transmission method must be rapidly scalable from small to very large. The weakness of the Hotmail model is that a free email service requires its own mail servers to transmit the message. If the strategy is wildly successful, mail servers must be added very quickly or the rapid growth will bog down and die. If the virus multiplies only to kill the host before spreading, nothing is accomplished. So long as you have planned how you can add mail servers rapidly, you’re okay. You must build in scalability to your viral model.
A truly viral product emerged from targeting a truly viral problem in the digital age, known as attention deficit disorder. Allowing people globally to channel their nervousness into an entertaining handheld device has allowed for the viral spread of Fidget Spinners. The products modest beginnings spread virally through school children and later through to adults. We started seeing fidget spinners in social media, memes with fidget spinners, fidget spinners distracting people while crossing the street, and of course, fidget spinners in the impulse purchase section of your local supermarket. This little product achieved a viral marketing status through providing a ‘solution’ to a viral problem and bringing about a world full of fidgetty temptation.