It depends on what you mean by changing the world. For instance. The MS team working on Microsoft word upgrades doesn't change the world in a meaningful way, wh

It depends on what you mean by changing the world. For instance. The MS team working on Microsoft word upgrades doesn't change the world in a meaningful way, when was the last time you heard "Now MS Word has feature X, my life is saved, my children are healthier." Meanwhile, I know two brothers who from a simple YouTube channel (not even devs) whose followers have topped the Kiva loan program, raised millions and millions of dollars for charities around the world, are actively educating people of all ages about history, literature, current events and science. One of the brothers has made the New York Best Sellers List in young adult fiction with a book about the struggles of cancer. With less capital they are decreasing world suck more than MS Word development team. So, what about apps and web apps? A really cool childrens book that is interactive and encourages kids to read or learn about a cool and important topic, I would argue, will have greater net value than Angry Birds even if the audience is smaller. An app designed for companies (like electric companies) to use, that forecasts weather conditions that aren't storm conditions but are more severe than the company can operate saves lives, while the market is small. I'd argue saving even one life or helping teach one child how to read is changing the world in a big way. My message of the day, "Do work that matters."