I have been using pinterest since I opened my store (early December). I have a few repins and less than 10 etsy views coming from pinterest.
But pinning and get repinned by other sellers in terms of promoting each other, does really worth the fuss? Our time is valuable.
The way I act as a buyer when I want to browse or buy an item, is navigating to the website, use the search function and see what my options are. I have never used the social media to search, or get inspired by an item and go for a purchase. This is an other point that discourages me from thinking of pinterest positively or considering it or any other social media as a source of sales. Traffic maybe, sales no.
But again, this is just me. I hear other people in forums praise the social media. Perhaps I am not that experienced to tell.
I do continue pinning mine and repinning/favoriting other sellers' items, but truly, I do it whenever I have enough spare time and have rather limited, not to say none, expectations.