For example, you can design digital products, like animal clipart or a downloadable wedding poem that could be printed by the customer. Your design could be resold thousands of times without needing to create each item or ship it. Once you create your digital product and list it on a site like Etsy or Ebay, the revenue flows in with little oversight.

EVA as a performance indicator is very useful. The calculation shows how and where a company created wealth, through the inclusion of balance sheet items. This forces managers to be aware of assets and expenses when making managerial decisions. However, the EVA calculation relies heavily on the amount of invested capital, and is best used for asset-rich companies that are stable or mature. Companies with intangible assets, such as technology businesses, may not be good candidates for an EVA evaluation.

Rental properties are defined as passive income with a couple of exceptions. If you’re a real estate professional, any rental income you’re making counts as active income. If you’re "self-renting," meaning that you own a space and are renting it out to a corporation or partnership where you conduct business, that does not constitute passive income unless that lease had been signed before 1988, in which case you’ve been grandfathered into having that income being defined as passive. According to the IRS, "it does not matter whether or not the use is under a lease, a service contract, or some other arrangement."

The reading is organized as follows: Section 2 develops the concept of residual income, introduces the use of residual income in valuation, and briefly presents alternative measures used in practice. Section 3 presents the residual income model and illustrates its use in valuing common stock. This section also shows practical applications, including the single-stage (constant-growth) residual income model and a multistage residual income model. Section 4 describes the relative strengths and weaknesses of residual income valuation compared to other valuation methods. Section 5 addresses accounting issues in the use of residual income valuation. The final section summarizes the reading and practice problems conclude.
One of the things I'm surprised your article doesn't mention is the tax advantages of this type of investment. The depreciation and rehab costs (purchasing distressed properties) can be huge deductions to ones income taxes, which none of the others have. Then, along with the appreciation of real estate, this passive income investment outperforms the notion of maxing out my 401k as well.
Residual income is different from a salary, or linear income, which is paid out strictly based on the number of hours a person works. Someone who works on a salary is often said to work “paycheck to paycheck.” This is because he pays all of his bills with his first paycheck and then must wait until he gets paid again to have more money. Ideally, someone will work hard building up a business so that he can enjoy the residual income once his goals have been met. Then he can work on additional projects while still earning money from his business.
One of the easiest ways to get exposure to dividend stocks is to buy ETFs like DVY, VYM, and NOBL or index funds. You can also pay an algorithmic advisor like Wealthfront to automatically invest your money for you at a low fee. In the long run, it is very hard to outperform any index, therefore, the key is to pay the lowest fees possible while being invested in the market. Wealthfront charges $0 in fees for the first $15,000 and only 0.25% for any money over $10,000. Invest your idle money cheaply, instead of letting it lose purchasing power due to inflation. The key is to invest regularly.
To save time and effort, a person can group two or more of their passive activities into one larger activity, provided they form an "appropriate economic unit." When a taxpayer does this, instead of having to provide material participation in multiple activities, they only have to provide it for the activity as a whole. In addition, if a person includes multiple activities into one group and has to dispose of one of those activities, they’ve only done away with part of a larger activity as opposed to all of a smaller one. 
Dividend stocks tend to be more mature companies that are past their high growth stage. Utilities, telecoms, and financial sectors tend to make up the majority of dividend paying companies. Tech, Internet, and biotech, on the other hand, tend not to pay any dividends because they are reinvesting most of their retained earnings back into their company for growth.
I had to get out. I actually had this random Facebook ad come up in my news feed (go figure) and it eventually led me to a webinar that taught on how to start an email marketing business (which is, by the way, the most profitable form of affiliate marketing – or ANY marketing for that matter). I listened through the whole 2 hours, completely mesmerized. By the end of it, I knew what I was going to be focusing on to help my family out of the pit of debt we were in and into a world free of financial stress. I didn’t know if it would actually work, but eventually it lead to EXCESS income!
As doctors, we most likely fall into the first category. We may be rich in the sense that our salaries are in the higher economic range, however, because of our expenses (houses, cars, student loan debt, private school tuition, practice overhead, etc.) and sometimes poor decisions, we have a tough time accumulating any real wealth. We’re also handicapped by the fact that we start along this financial journey relatively later in life.

Real Estate is the most widely known avenue to pursue for passive income. Most people think of investing in Real Estate by buying a house or apartment complex and renting it out. While we will be investing in actual property later, we will show you other ways to invest in real estate through REITs and a website called Fundrise. For more information on passive income through Real Estate check out this (link).

Owning an investment property can result in both potential appreciation value over the long-term and direct tax benefits of depreciation. However, acquiring an investment property often requires large upfront capital ($100K to several million dollars depending on the type of asset), and lots of hands-on work. Furthermore, as with any investment, investment properties carry the risk of large, unexpected, and costly liabilities, which many investors do not have the experience or time to effectively handle. An investment property also is relatively illiquid—meaning you can sell at any time, but the sale process can often take months and may be unsuccessful.
In equity valuation, residual income represents an economic earnings stream and valuation method for estimating the intrinsic value of a company's common stock. The residual income valuation model values a company as the sum of book value and the present value of expected future residual income. Residual income attempts to measure economic profit, which is the profit remaining after the deduction of opportunity costs for all sources of capital.