Ghost is made by an independent non-profit organisation called the Ghost Foundation. We are 100% self funded by revenue from our Ghost(Pro) service, and every penny we make is re-invested into funding further development of free, open source technology for modern publishing.
The version of Ghost you are looking at right now would not have been made possible without generous contributions from the open source community.
The main thing you'll want to read about next is probably: the Ghost editor. This is where the good stuff happens.
By the way, once you're done reading, you can simply delete the default Ghost user from your team to remove all of these introductory posts!