Okay, so, WordPress.com has a built-in stats package that I use to figure out how many people have visited this blog. And this stats package shows that it gets between 50 and 250 unique visitors per day, so I assumed that was pretty much the readership of this blog. However, a friend just asked me how many monthly visitors I get, and I was like, "Well, wordpress.com shows that I get about 2000-2500, but I am pretty sure that is just the sum of my daily unique visitors."
However, I decided to do some checking up on this, and it began to appear, from reading this help page, that the wordpress stat for each month IS monthly unique visitors. In which case, that would mean that more than 2000 different (non-spam) IP addresses have landed up at this site in the last month. That's not an earth-shaking number, but it IS roughly ten times as many readers as I thought I had, which definitely was enough to shake me.
So I decided to confirm it by going forth and manually totaling up the visitor numbers for each day in August and discovered that they actually DO total up to more than the monthly visitor number. Insane!