You already know what a USB is. It’s that connector you use to put a stick into your computer, to charge your phone (probably micro-USB), etc. So, what’s the big thing with this “-C”? Well, the vision is to have one cable that is capable of doing everything (if all devices have USB-C).
Connect a external hard-drive to your laptop or phone? Yes.
Connect your phone to your laptop? Yes.
Charge your laptop or phone? Yes.
Connect your laptop to a external graphics card? Yes.
Connect your laptop to a monitor? Yes.
Connect your laptop to a monitor, charge your laptop, use external speakers, a webcam, all just one cable away? Yes.
So, as you can see, this new connector is pretty insane. It’s what we dreamed of from the beginning. I can see a near future where we will have just USB-C connecting everything. Even the power outlets sockets can be type-c and you can connect your fridge to the socket using USB-C.
One thing to point out is that not all USB-Cs are the same. Some just carry data, they are like a normal USB but with the type-c connector. Other use what’s called “thunderbolt 3”, this can carry a lot of data and power to charge your device.
I am using the new MacBook Pro that only has USB-C ports and at the end of the day you have 2 options.