Image Source: Wikipedia's entry on Wikipedia.
Today is Wikipedia's tenth birthday. Founded on January 15, 2001 by Gen Xers Jimmy Wales and Larry Sanger and others, the site embodies many of the original ideals that surrounded the internet. It encompasses some of the best of the Web's possibilities in being direct, useful, free, democratic and informative - albeit with sometimes dubious editing and debates on particular entries. Time has a report on Wiki's ten most memorable entries here. Of those, the three that caught my eye were Wiki's List of Unusual Deaths; the number 6174; and the Medieval Dancing Plague.
Because it is free and widely accessible, Wikipedia is probably the most widely used encyclopedic resource commonly used today. It is a triumph of the Millennial reimagining of the Neo-Classicisal rational ideals of the eighteenth century on the internet. The original French Encyclopédie was published from 1751 to 1772. Encyclopedias as a form of reference source are 2,000 years old. The first one we are aware of (according to Wikipedia) is Natural History by Pliny the Elder.