Next Blog Button

Occasionally, I'll get a little spike (well, it looks big, since my traffic is pretty low, but it's not big) in my visits when looking at my site meter stats, and looking at the referrals and seeing lots of completely unrelated Blogger blogs that don't link to me leads me to the conclusion that I have somehow magically gotten into the rotation for the Next Blog button. So I was wondering if anyone knows how that happens. I don't really see much of a pattern to the times that I've noticed it. Anyone have any ideas?