Kindness is a major force in the modern economy. It stunned me, as an economist steeped in how self-interest guides commercial decisions, to realize how big a role kindness plays today.

Allison Clarke is a consultant and speaker who performs at least one act of kindness daily, a habit that began as a short-term project and morphed into a way of life. Clarke says, “Acts of kindness can be almost effortless. They can also alleviate depression, reduce overwhelm, and be the medicine a team needs to gain connection and trust.”

My sailing support vehicle is a minivan with electric doors. When one wouldn’t work, I hit the online forums. One writer had paid $40 for a diagnosis—but the mechanic couldn’t figure out the problem. Another had been quoted over $250 for a fix. But some guy named Steve said pull out fuse number 13, wait 30 seconds, replace the fuse and give the door a try. It worked.

The kind thing is that after Steve fixed his own problem, he took the time to help others. It was just a short post on a forum, eight lines in total, but it saved readers a ton of money, time and aggravation.

What can kindness on YouTube help you do? Fix a leaky toilet, disassemble most any piece of machinery, learn how to juggle. And the vast majority of the contributions were acts of kindness.

I look around my office at the pieces of equipment which I bought after reading user reviews on Amazon or some other website: my scanner, my printer, my cell phone. Reviewers are not paid but act out of kindness. Reviews are a major reason that e-commerce has boomed. And I’ve found reviews to be more informed than most store salespeople—and more trustworthy. So when you see Amazon trucks in your neighborhood, and an empty building where K-mart used to be, the kindness economy is at work.

I recently bought a new woodworking router. That act of commerce followed a question that I posted on a forum about routers with dust collection ports. In less than 24-hours several people had answered my questions and offered their advice. Pure kindness, which triggered my eventual purchase.

Self-interest is a powerful force, and a very positive force, but not the only one at work. Pure kindness has amazing impacts on the economy.