1) It is an E-comm platform for selling Goods & Services
2) It is an app development platform that allows other businesses to be built on top of it with sites and apps (ie- the apps are integrated to manage distribution, inventory, warehousing, invoicing, marketing, CRM, etc)
As an example, Bold Commerce has become a significant company because of the Shopify platform. They are the largest developer of custom Shopify apps and sites in the world – they recently raised $16.5M (USD) to scale further
Overall, Shopify processes a huge amount of GMV through the platform and, of that, its Net Revenue is still in the Billions each quarter. The article may be misleading to some, given the headline, but Shopify has a significant impact on the economy globally.