1. MLM/network marketing. This industry has been around for a long time, but it is still one of the most profitable ways to start earning passive income either online or offline (I am personally involved in network marketing, and it is the ultimate way to leverage your time & others' time to generate a substantial income stream). The great thing about network marketing in the 21st century is that with BASIC internet marketing skills you can learn to generate a consistent flow of targeted prospects on a daily basis...so you don't even have to talk with family, friends or coworkers if you do not want to.
2. Affiliate/Google Adsense websites. Monetizing niche websites with either Google Adsense or affiliate marketing (Clickbank, Amazon, etc.) are two excellent ways to generate a passive income stream online. However, when it comes to residual income business opportunities this has more of a learning curve than network marketing.
3. Domain flipping. This is where you buy & sell websites for profit. You can simply buy domains & resell them at a higher price, or you can create entire websites, get them to making a certain amount of $ per month, & sell the sites for 12-20X the monthly revenue. While this is a wildly profitable way to create residual income online, there is once again a steep learning curve.
My suggestion for those that want a simple, easy to start residual income opportunity would be to get involved with network marketing. In fact, I provide free training for anyone who wishes to learn the ropes of MLM, and find out what it takes to succeed in this industry. If you want to see exactly how I do it, simply CLICK HERE and get your free guide.