From Conservapedia Wolfram MathWorld is an online math encyclopedia. All its content is approved by an chief editor (Eric Weissman). They accept contributions from the general public, but they don't have a free-wheeling wiki as do other online projects such as Conservapedia and Wikipedia.
The website content is freely available and run pro bono by Stephen Wolfram's company, Wolfram Research.
Their anti-spam question was:
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Categories: [Mathematics] [Websites]
ZWI signed: