Fourteen years ago, I began teaching history at a public high school in the Bronx. My students and colleagues were awesome, but I could see that the school where I was teaching did not have the same resources as the schools I'd attended. My colleagues and I spent a lot of our own money on copy paper and pencils, but we often couldn't afford the resources that would get our students excited about learning. We'd talk in the teachers' lunchroom about books our students should read, a field trip we wanted to take, or a microscope that would bring science to life. "Crowdfunding" wasn't yet a word, but I figured there were people out there who'd love to help -- if they could see where their money was going. Fourteen years later, more than a million donors have supported projects reaching 10 million students in low-income communities, demonstrating that micro philanthropists can have a macro impact.