In 2004, Jessica Jackley set out for rural Kenya, Tanzania, and Uganda to perform an impact evaluation for the Village Enterprise Fund (VEF), a San Francisco Bay Area nonprofit that makes modest grants and loans to small businesses in East Africa. A few months later, her husband, Matt Flannery, then a computer programmer at Alviso, Calif.-based TiVo Inc., came to visit her. As the couple traveled around the country interviewing small-business owners, they talked nonstop about the best ways to help Africa’s struggling entrepreneurs. One year earlier, Jackley had heard Muhammad Yunus, the…