VigLink worked to connect about 55,000 merchants to Tumblr's site, the company says. When blog visitors click one of these new links, they're taken to a merchant's website, where they may then make a purchase. In that case, Tumblr will show up as the referrer and then receive the commission.
http://computerissuescenter.blogspot.com/2015/07/get-rid-of-apiviglinkcom-step-by-step.html
https://techcrunch.com/2016/09/09/tumblr-to-roll-out-affiliate-links-across-all-users-blogs/
Absolutely zero value to the merchants here. The links were there already there and generating visits and now the merchant has to pay for them? Nah, I think we will be opting out of that one. Same with the deal they made with Reddit.