The National Retail Federation (NRF) reports that there’s been a record $59.1 billion in sales racked since Thanksgiving Day. Even more impressive is the fact that 40.7% of these transactions were brought in from online sales. And those numbers are pre-Cyber Monday, so they’re sure to skyrocket even higher once the biggest online shopping day of the year is over and done.

But what’s really interesting is that there’s been a serious about-face when it comes to social referral traffic. Overall, referral traffic to leading ecommerce websites from social networks is up a significant 44.32%, but while in past years Pinterest has been a great driver of referral traffic, so far it’s been down 10.41%. And on the flip side, Facebook has traditionally been a less than effective social referral driver, but has increased 72.62%.

What makes this even more interesting is that these stats are in light of Pinterest’s recent release of its long-awaited API, which allows big-brand, third-party retailers like Target, Zappos, Disney, and Wal-Mart to embed pins showcasing their most popular products directly on their websites. It also helps Pinners post content from retail websites more seamlessly, and in theory, increase user engagement and drive more traffic to the retailers’ websites.

Since shoppers referred from Pinterest spend on average twice the amount of a shopper referred by Facebook, this is could potentially be a needle-mover—although by holiday sales so far, it seems like the only direction the Pinterest needle is moving is downward.