No matter who said it first, we've all been advised that eternal vigilance is the price of liberty. And so too is it the price of an online encyclopedia anyone can edit. The World Wide Web is unfortunately well-known for its trolls and griefers, and Wikipedia is not immune.
One particularly troubling manifestation of this reality is the existence of Wikipedia hoaxes. The long list of discovered hoaxes is proof that Wikipedia's open-editing policy is a double-edged sword: troublemakers will add false information, and stalwarts will identify and root it out.
Sometimes hoaxes are created by accident, or to prove a point, but most of the time it's for the lulz. And hoaxers are not the only ones titillated: media stories list the "best hoaxes" and marvel at the "longest-running" examples (current record: 10 years, 1 month).
All we know for sure: more Wikipedia hoaxes lurk, waiting to be discovered.