USB Type-C is the connector itself. This name follows from the USB 2.0 connectors of Type-A (host side) and various forms of Type-B (device side), including standard B, mini-B, and micro-B. With USB Type-C, there is no distinguishing the power and data role based on the physical connector. Both devices and hosts, sources and sinks, will have the USB-C receptacle. USB-C cables have the same plug on both ends.

The spec includes mechanical, electrical, and some functional details on how to use it. Some of these functions include signaling data and power roles, available power, and whether or not a device is an accessory. The USB Port Controller Specification provides a common interface to ICs that are directly connected to a port. The goal of this spec is to ease the development of software.

USB Power Delivery

USB Power Delivery is where most of the revolutionary features are. "Power Delivery" is a bit of a misnomer, because it does so much more. This is the spec that describes how to swap data roles, swap power roles, move Vbus to different voltages, and use the pins on the USB-C connector for other purposes like DisplayPort. This is what lets you plug your laptop into your monitor to present slides while recharging and running a full USB 2.0 hub, all with one cable.

Technically Type-A and Type-B connectors can use Power Delivery, but I've never seen it implemented. The spec that lets your phone charge at high speed if D+ and D- are tied together is the USB Battery Charging Spec. Power Delivery will likely be a de facto replacement for Battery Charging as more phone go to USB-C, but it is not a direct replacement.

Conclusion

I hope this helps clear things up. The important take away is that USB 3.1 is the overall spec, and each of these new features and connectors are parts of that spec. In part 2, I will go into more details on the Type-C spec.