Can someone explain how 'Fatbirder' ranking works?

I have been gratified over the past few months (since I joined the Fatbirder's Top 1000 ranking system) to watch Birds of the Heath rise up to the second 'page' on the site. At one point, BoTH reached 84th spot: for a personal blog, I find that most surprising.

Recently, because of lockdown, presumably, the number of daily 'hits'  has averaged around 350 - 400: despite this, my Top 1000 ranking has dropped by 10 or so places. However! There are three ways you can inspect your daily position: overall ranking (today that's 95) inward traffic (Position 2 today) and outward traffic (Position 14)

Now, while I am, as I said, delighted to see that my blog seems to have achieved an audience, I was never under any illusion that it would compete with the 'big boys', many of which are actually commercial sites or are sponsored by bird-related companies. I'm just puzzled by what, if anything, the various tables mean!