Below the fold
While certainly there were more important things to test, it became clear that they were about to invest technical resources, and fairly sophisticated analytics and visitor behavior tools to track a metric that that they probably wouldn't care about in a month. They might not even have a fold in a month.
Half kidding, I told them to just put the terms FUCK YOU below the fold and see if anyone complained. Obviously I was just trying to make a point, but the sentiment was real. Rather than automating something sophisticated, putting some sort of IRRESISTIBLE call to action (80% off today only, or FREE LUNCH click here).
The point is, WHAT YOU TEST IS more important than HOW - but getting better and better (doing it faster, with less resources and producing roughly the same learnings/outcomes) at testing the wrong things will give you extra spins of the startup slot machine, ultimately increasing your chances of winning.