If you have specialized knowledge in a certain topic, you can put together an online course to teach others. For example, if you have experience in real estate investing, you can create an online course “Real Estate Investing 101”. The benefit of an online course is that once you create the course material, you can sell it to as many people as you want.
I have only dabbled in drop-shipping before when I had an eCommerce platform 6 years ago or so. I think it is something that you could do on the side, but you would want to do in depth research on the industry you want to get into before setting up shop. It may be a little less passive up front, but over time you could take your hands off the wheel.
What I did: I first identified my favorite places in the world to live: San Francisco, Honolulu, Paris, Amsterdam, New York City, and Lake Tahoe. I then looked up the median rent and housing prices for each city. Then I factored in private education costs for two kids to be conservative given I may not have two kids and public schools are often good enough. After calculating all vital costs, I then did a self-assessment of how happy I was making $50,000, $100,000, $150,000, $200,000, $250,000, $350,000, $500,000, and $750,000. I decided working 20 hours a week making $200,000 a year is the best income balance for maximum happiness. 
The term Marketing comes from the words ‘market’ and ‘getting’; conquering the market. The term marketing has been around for over a 100 years. Today, it’s still about large companies wanting to conquer the market, gain market share and (new) customers. Marketing methods are comprehensive and Viral Marketing is a relatively new way. This technique increases the awareness and reach of a product or brand by using social media. It’s word-of-mouth advertising using the internet. The more people who know about it, the better. Each company that uses a marketing communication goal to express a specific marketing message can do so by publishing digital video clips, for instance. These days, commercial organisations employ viral marketing to generate brand recognition, launch a new product or draw attention.
John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Selena Maranjian owns shares of Amazon, Costco Wholesale, National Grid, Realty Income, and Verizon Communications. The Motley Fool owns shares of and recommends Amazon, eBay, National Grid, and Verizon Communications. The Motley Fool recommends Costco Wholesale, Lowe's, The TJX Companies, and Welltower. The Motley Fool has a disclosure policy.
Residual income is money that is earned on a recurring basis, typically as the result of a single original action. Rather than earning an hourly wage, residual income is typically generated through an initial investment of time or money with the goal of earning continuous payments. Once the initial investment, product, or service is made, the ongoing income that is earned is generally passive in nature.
The first thing that we need to calculate is the number of new customers that each existing customer is able to successfully convert. This turns out to be an extremely important variable, and is known as the Viral Coefficient. The formula to calculate the viral coefficient is pretty simple: multiply the number of invitations by the conversion rate.
Please remember that your passive income may not be higher than your active income. Your goal should be to achieve a combination where both incomes are greater than your current active income.  Don’t expect too much, but always remain optimistic. You and I may not be as lucky as J.K. Rowling or Dan Brown, but we both certainly deserve a good vacation.

Viral content usually has a well-designed viral strategy behind it, it is, in part, also due to luck, but creativity and preparation are also extremely important… for this reason, to get to know this world a little better, I would like to tell you today what the definition of this concept actually is, how a viral campaign works, the advantages or viral marketing and show you our favorite examples.