The traffic-driving impact of The Big 3 social networks – today, let’s rank them as Facebook, Twitter and Pinterest – is being constantly measured, calibrated, then re-measured and re-calibrated, it seems. This is important as marketers want to know on which networks it would be wisest to maintain a vibrant presence. The answer: all three. But it’s clear that one of these Big 3 is not just driving traffic, but big-ticket sales. Hint: it ends with “interest.”

The latest data come from social commerce platform enablers at Shopify. Shopify analyzed traffic data from over 25,000 Shopify online stores and drew the following interesting conclusions. It writes on its blog:

…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.

Here’s the breakdown in, yep, infographic format: