Aah, I see.
Circles are basically for this; If someone you find on Etsy has similar tastes to your own, that's when you should add them to your circle. Because you'll see the items they've liked in your Activity Feed. And 9 times out of 10, if they're in your circle for the reason above, the stuff they like will be stuff you like or lead you to other great items.
I used to add people to my circle for adding my shop to their faves, thinking; "Oh, well if I show them that I'm active on Etsy by adding them to my circle, maybe they're likely to buy something?" Don't know if that's true and it may still be in some cases.
But, by doing this I always found that my activity feed was full of things I had absolutely no interest in. Not that it matters really I just don't like clutter, unless it's all awesome paintings and illustrations!
Looking at your sales I'm sure you're doing something right... I don't know. I'd keep it up, whatever it is!