To give you a preview of this post, what you will learn is that there are two key parameters that drive how viral growth happens, the Viral Coefficient, and the Viral Cycle Time. To fully illustrate the arguments, I have included two spreadsheet models (embedded) that you can play with interactively to see how viral growth works. There is a risk with this level of depth, that some readers will find this too technical, and if you find yourself reacting that way, may I recommend that you jump straight to the conclusion, which is under the heading Lessons Learned towards the bottom of the article.

Viral advertising is personal and, while coming from an identified sponsor, it does not mean businesses pay for its distribution.[6] Most of the well-known viral ads circulating online are ads paid by a sponsor company, launched either on their own platform (company webpage or social media profile) or on social media websites such as YouTube.[7] Consumers receive the page link from a social media network or copy the entire ad from a website and pass it along through e-mail or posting it on a blog, webpage or social media profile. Viral marketing may take the form of video clips, interactive Flash games, advergames, ebooks, brandable software, images, text messages, email messages, or web pages. The most commonly utilized transmission vehicles for viral messages include: pass-along based, incentive based, trendy based, and undercover based. However, the creative nature of viral marketing enables an "endless amount of potential forms and vehicles the messages can utilize for transmission", including mobile devices.[8]
Online courses have exploded in the past five years. Experts and creators can now create video courses to teach others their craft. A course can be about anything that people want to learn. Friends of mine have created courses and say the amount of effort is similar to writing a book. But once its done and starts to sell, it’s a solid passive income stream.

Income-generating assets are another of many passive-income opportunities. A classic example is making money in real estate via owning rental properties. It can seem perfect: You buy an apartment building or house, rent it out, and then sit back and collect checks every month from your tenants. The reality isn't always so rosy, though. For one thing, you'll need to maintain and repair the property, as well as paying taxes on it and insuring it. It may not always be occupied, either. You may have trouble finding tenants, or finding tenants who pay their rent reliably. Some tenants may damage the property, and others may be hard to get rid of. You'll be the one they call in the middle of the night if the roof is leaking, and you'll have to clean and perhaps freshen up the property between tenants. You can outsource much of this to a property management company, but it will take a cut of your income, often about 10%.

The reason to make use or virality, the ease in spreading and sharing, is however a double-edged sword. We cannot forget that in this type of campaign, a large part of the control falls into the hands of the users, and we risk the message being misinterpreted or parodied. On the other hand, a successful viral campaign can work miracles for your brand’s results.