James W. Prall, a system administrator and tech support contact for all research computing at the Edward S. Rogers Sr. Department of Electrical and Computer Engineering (ECE) at the University of Toronto. That’s his day job. When not doing that, Mr. Prall spends his free time developing and maintaining a list of some 2,100 climate scientists and ranking them according to whether or not they are climate deniers. Mr. Prall’s academic background is unclear, although his blog site informs he is a Virgo...
... So now, how do you create a blacklist? First you need a doctrine against which to draw the blackist of non-believers. In their paper, our pool crew first created a list of good scientists, those who “support the tenets of [anthropomorphic climate change] outlined by the Intergovernmental Panel on Climate Change.”
Doesn't appear that anyone "signed-up" for the list, more like they were appointed.