Hello, and kudos to the Brilliant staff for the new ratings system. I think an ELO system like this one fits the purposes of the site.
I noticed that every time I view a problem on Brilliant, my rating drops a few points even if I did not enter an answer. However, a print feature is available and would avoid such deductions. Wouldn't it be unfair for those who do not have access to printers? (Users may just copy the problems by hand most of the time, of course, but still...)