I don't think the author is "keeping track" of anything. If I say, "Hey, will you review my YC application?" and you say, "Sure, but get it to me before Wednesday or I won't have time." and I say, "Will do!" and then you never hear from me again, you won't be recommending me for anything. And likely, you won't take the time to help me if I try to reconnect, unless I have a pretty good reason I flaked.

It's not a list, it's human nature. You invest in things that show promise, and the behavior outlined above doesn't show promise.