[atomflunder3000]

I think they were saying Elo system as kind of a general ranking system idea instead of the actual algorithm.

You could probably use some kind of pairwise ranking algorithm (like anything based on the Bradley-Terry model) to rate human vs. AI contributions, but that would take a lot of manual effort. Google is using it to (supposedly) improve their searching algorithms. They give testers two different versions and ask them what's better.