This is a Turing Test: 5411

[Oran]

This is on people's profile pages. What does it mean. I know what a Turing Test is, but 5411...what is that?

[Carleas]

It's a way of filtering out essentially all robots that try to sign up. People have to put '5411' in a box to prove that they've read and understood the request to do so, thus suggesting that they're either a human or a machine clever enough to discuss philosophy.