It's just a fun thing I saw on Patrick Nuss's log (Pink_Socks) a while ago. You are presented with a map measuring a statistic of some sort presented in various ways and you're supposed to try to figure out what the map is showing.
I signed up so they show up in my inbox on Monday morning and I take a look. I usually make a random guess and see how I did as they give hints during the week. I'm close fairly often but don't usually spend any time researching anything to check my guess. This week I was pretty sure my guess was right, checked a few things and am convinced my guess is right.