Oreo did in fact have 15 person strong social media team standing by to jump on anything that could have happened during the evening but you can still be this viral with a one person team if you can keep on top of current trends in your industry. Learn from this example of great viral marketing and use current events to position your product in the middle of it in a positive light.
Another way to generate passive income is to invest and be a silent partner in a business. This is very risky, but with risk comes the potential for high returns. For example, several years ago both Lyft and Uber were looking for private investors to invest in their companies. Today, they are worth billions - but you as an investor would only reap that benefit if they go public via an IPO, or get acquired. So, it's risky.
Viral marketing or viral advertising is a business strategy that uses existing social networks to promote a product. Its name refers to how consumers spread information about a product with other people in their social networks, much in the same way that a virus spreads from one person to another. It can be delivered by word of mouth or enhanced by the network effects of the Internet and mobile networks.