Shilad Sen, Math, Computer Science, and Statistics, will present "Understanding Wikipedia." Wikipedia's four million articles constitute the most widely read reference on the web. During my sabbatical last year Sen immersed himself in Wikipedia. He explored Wikipedia's article quality norms, measured the gender gap among editors, and mined semantic knowledge from Wikipedia to power his Macademia website. This talk will describe these projects, and tell the story of how Sen came to research Wikipedia.  All faculty are welcome.  Lunch will be provided.