I used to, but the truth is, in the time it takes to look at who favorited my shop (or even to look at treasuries I've been placed in), I can do things that are more likely to help my shop, such as listing more inventory, other kinds of online promotion, or studying and tweaking SEO. I think it's a waste of time, and all it does is encourage those who favorite shops or items for the purpose of self-promotion to continue doing something that doesn't work. Skip it, I say.