Libraries existed before, but v.18.0.0 made them global. You could now drag a color swatch from a library directly onto a vector layer. You could share a "Library" link with a client, and if you updated a logo in the library, it asked every linked document if they wanted to sync. This was the birth of Adobe's ecosystem lock-in.
In 2013, Adobe announced the Creative Cloud (CC) subscription-based model, which marked a significant shift away from the traditional software licensing model. The CC platform provided users with access to the latest versions of Adobe's creative applications, including Photoshop, as well as a range of cloud-based services and features. Adobe Photoshop CC 2017 v.18.0.0