If you have a blog or some other property that has visitors, you might profit passively via affiliate advertising. For example, imagine that you write a blog about movies. You might review some books about movies, and then link to them on Amazon so you get a cut of the purchase price when anyone buys books through the links. If you blog about hiking, you might promote some hiking gear you recommend on the blog, again generating passive income if anyone buys any of it.
Apple maintains it’s viral appeal, with the iPhone X through their launch of the "Selfies on iPhone X" campaign. The secret to this example of viral marketing (which has clocked up over millions views both online and offline) is very simple: a product so great that it turns people into fans of the brand all on its own. People love themselves. If they have the possibility of spreading this love digitally through selfies, it’s almost a guaranteed win. The iPhone X’s brilliant selfie feature spread virally through various media forms before apple repurposed the viral content into one masterpiece, the iPhone X selfies film. As one of the YouTube comments says, “It’s the most beautiful thing I’ve ever seen”… This viral marketing through video has allowed Apple to spread key features such as their Portrait Lighting effects and their TrueDepth camera.