However, residual income typically has an expiration date, especially if it is being earned through a business. Effort must be continuously put into the business in order for someone to continue to receive residual income. Businesses must continue to market themselves in order to remain relevant. The best way to look at residual income in this sense is that it is a part-time job that earns full-time income.

This has become a popular business model for online entrepreneurs over the past several years, and will probably just continue to grow in popularity. The best thing about selling online courses is that once you do the up-front work in creating the course and setting up your marketing strategy, you can get paid over and over again for work you do once.
What does that mean for you? It means Nielsen will pay you $50 a year to keep their app on your favorite internet browsing device. The app itself collects statistics on your internet usage anonymously, so you never have to worry about any data being linked to you. And the best part is, the app takes up barely any space and doesn’t slow down your phone or tablet at all!