Molly, I've seen the same seller with the same items show up several times on the same page as well! It's frustrating... Let us know what you find out with your research. I will say that the snazzy book I added to the "book review" page talks about how beneficial to SEO Pinterest can be. Because each pin maintains a link to the original site, the more people who pin your item, the higher your SEO for online search engines. I think the same may apply to Facebook - the more people who "share" your links, the higher your SEO. The added benefit of course is the more people who are exposed to your items, the more potential customers you have :o). However, if I'm reading things correctly, Etsy works with relevancy instead of SEO? So it depends on where you want to build your market...