I use a lot of social media: twitter, facebook, tumblr, pinterest and sometimes other sites like craftori or wanelo. While few people see my Facebook page due to how FB hides pages from people who don't interact, FB is the only site from which I actually get sales. I think it's because the people who like my page are really my target market. It's not a lot of sales, but it seems like if a sale comes from another source other than Etsy search, it is because someone saw something on FB and either wanted it or it generated a custom request. Long answer, but for me, Facebook is successful.