Nearly every day, the Wikimedia Foundation gets a note of thanks -- like the one from a school administrator who say she is "so grateful" her kids can access Wikipedia; and the note from a dad who said Wikipedia explained his son's medical condition and "what questions I should be asking the doctor"; and the note from a social worker who reads Wikipedia aloud to elderly patients to help them "remember the past."Wikipedia is the world's knowledge source -- an online destination with 40 million articles in almost 300 languages. Every month, more than 400 million people rely on Wikipedia and our sister sites, and each of these 400 million users has a story of impact and learning. The stories come from small towns and big cities across the United States and from similar places around the world -- like Cape Town, South Africa, where students at a school with makeshift classrooms are using Wikipedia to study. The students at Sinenjongo High School use their mobile phones to connect with Wikipedia. In seconds, they find facts that engage their minds and inspire them to excel in school projects. Wikipedia has a long-term impact, they say. "After school, I want to have a job that I will earn good money so that I can provide for family and live my life to the fullest -- not forgetting about giving back to my community," said one student, a teenage girl named Nezisa Mdludlu. "I want to be a role model. Wikipedia means the world."Donors provide our entire budget. By pooling donations of every size, we improve Wikipedia -- and make a real difference in people's lives. Wikipedia, our readers say, is a gift -- a gift of knowledge that keeps on giving every time people use it.