The article ends with: > As we tear down the boundaries between Partners and Merchants, we connect merchants with the entrepreneurs ready to solve their proble

The article ends with: > As we tear down the boundaries between Partners and Merchants, we connect merchants with the entrepreneurs ready to solve their problems. "Partners" are a key part here, I think. Merchants can run their own code or possibly install 3rd party partner plugins. This is similar to the way 3rd party Wordpress Plugins work except, unlike PHP, they are small, fast, and safe. They can also run in a multi-tenant Shopify environment that scales safely. As far as I can tell, the use case is similar to database triggers or custom web request filters: enhance the standard request flow with custom actions.