About page: "Add Skype user quixeychallenge as a contact. A working microphone and speakers/headphones are required. [..] We'll Skype call you when it's your turn."
And since the registration form is required before you do anything, and it is one form needing an email address, I think that counts as 'telling you about the need for an email address before you get involved' too.
"The algorithm will be implemented as a Python 3.x function". - The instructions page, the first item. (http://www.quixeychallenge.com/instructions).
About page: "Add Skype user quixeychallenge as a contact. A working microphone and speakers/headphones are required. [..] We'll Skype call you when it's your turn."
And since the registration form is required before you do anything, and it is one form needing an email address, I think that counts as 'telling you about the need for an email address before you get involved' too.