Great info, Ryan. I am also trying to determine the value of comments. However, in my experience, the difference is too significant to make an exact decision.

There must be something behind it.

I have many articles that earned just $0. 01 without any comments in a first day. However, when one or two readers left comments, the earnings increased to $2 or $4 in a second day, all without any significant spikes in readership.