A2A, but Lance LaSalle’s answer says it all; thanks, Lance.
Executive summary: nah. In a recent answer, I was reduced to begging readers to upvote the other answer first. I’d link, but that would mean even more people upvoting my answer instead of the other one.
(Just Vote #1: Amy Dakin. That’s all I’m sayin’.)
I’ll add one metric *I* use for A2A, which also gets surfaced (at least some of the time) in the UI for answers: how many questions the poster has already answered on the topic. That can establish either that they know what they’re talking about, or that they’re at least persistent.