Twenty years ago, physicist Paul Ginsparg began a little project on his desktop: an electronic database to let fellow physicists share unpublished academic manuscripts without photocopying and paper mail. Over the past two decades, that project has revolutionized the way scientists share information. Today, arXiv -- a free scientific repository of research in physics, mathematics, statistics, computer science and related disciplines -- boasts 700,000 "preprint" articles, a million downloads a week and hundreds of thousands of contributors. To commemorate arXiv's anniversary and plan for the future, Paul Ginsparg presented "arXiv at 20: The Price for Success" at 3:30 p.m. on Friday, Sept. 23 in room 120 of Cornell University's Physical Sciences building. The talk was part of a day-long forum that also included meetings with publishers, societies and arXiv's scientific advisory board.