Via Shopify:
To better understand how Pinterest is effecting the ecommerce industry, we analyzed data from over 25,000 Shopify online stores. Interestingly, referral traffic from Pinterest to Shopify stores is equal to traffic coming from Twitter. Of that traffic, shoppers are 10% more likely to make a purchase compared to those who arrive from other social sites. Furthermore, of those purchases, the average order is $80 which is double the average order from Facebook. Pinterest has already become a huge player in the world of ecommerce.
Source: Shopify Blog