Etsy A/B Tests "In X Carts" Social Proof Message
Etsy has been a/b testing a simple and common social proof element on some of their product pages. They showed how many users have recently added an item in their shopping carts. The test now seems to have been rolled out with a slightly adjusted version of "In 3 carts" that's even higher up on the product page as the first element. Perhaps I didn't catch all the variations. Either way, this is further light-weight evidence in favor of the social counts pattern with many more a/b tests similar to this.
Highlighted UI Changes From This Leak
Added Social Proof Message
The variation contains additional bold red copy showing how many customers have this item in their carts.