He actually stated in the above referenced post that it was related to the traffic spike.
Where did he state it, I can't seem to find it?
"I turned on comment thread pagination to decrease the load. I'll turn it off tonight."
Comment thread pagination is not reducing the number of items visible on pages (eg, /newest, /ask, /news), it's splitting up comments onto multiple pages. Completely different things.
I took it to mean comment and thread pagination was turned on and or increased and therefore fewer items were shown on each page.