With the help of complex data mining and 2 million donors—26 percent of them repeat givers—DonorsChoose.org CEO Charles Best has built a $35 million nonprofit driven by long-term loyalty. His organization, growing at 20 percent annually, funds classroom projects and supplies requested by teachers in 70 percent of U.S. public schools.

“The internet can give a $1 donor the same kind of choice, transparency, and vivid feedback that Bill and Melinda Gates can get on a $1 million gift,” says Best.

His approach seems simple: “Get out of the way of the donor and recipient.” That means creating a direct connection that builds the relationship and proves the impact of a gift. Teachers post a vetted project, write thank-you notes directly to donors, and send photos of purchases made with the money. Donors giving $50 and more also receive handwritten notes from students. Here are Best’s other engagement tips:

Show the math. DonorsChoose.org is stuffed with stats to show how donors directly help classrooms nationwide. Such openness has funded 734,988 projects for 18.5 million students. Don’t think people are scared by numbers anymore, Best says.

Play to passions. More than 46,000 classroom projects reside on the DonorsChoose.org site, anchored by a simple-looking interface that cloaks the complicated filters enabling donors to identify preferred projects. That diversity means “citizen philanthropists” can support their passion, which ignites long-term loyalty.

Embrace human behavior science. Delving into brain science taught Best that donors give far more—and more often—if a teacher shares the same birthday or name, if their first project receives full funding, and if they know the teacher personally (half do).

“Enabling a donor to feel like a protagonist in a story and not just a passive check writer is important. So is giving raw, authentic feedback from people helped,” says Best. “Every nonprofit can give vivid feedback and a sense of impact.”