Saw this on Etsy - it might help (I'm also a bit mystified by it!)
" If someone "follows" (circle) you, they see whenever you heart something or make a treasury, or when you add someone to your circle. That's it. That's the extent of the "activity" people see.
It's not what we sellers do with it that will help, it is what buyers do that will help. You can ignore it entirely if you want. If someone who uses it hearts something from your shop, that item will show up in the activity feed of everyone in THEIR circle, thus exposing you to a whole bunch of people who may never have found you otherwise. You don't have to do a thing"