The computer that never sleeps - and without which nothing on the internet exists
Your laptop falls asleep the moment you close the lid. You switch it off at night and it rests. A server is the opposite - a computer that stays on all the time and never closes its lid. It has one job: to wait for someone to ask for something and answer right away.
Picture a night shift at a factory that never stops. While you sleep, someone there is awake and working, so everything is ready by morning. That's exactly what a server does. In the middle of the night, while you're reading news on your phone, it's awake instead of you, handing you the page the moment you ask for it.
A computer like that doesn't sit in your home. It sits in a large building, packed with a swarm of similar machines, working around the clock. Hosting is simply the place for your server there - you pay to use it, so you have your own night shift working for you.
Deploy is the moment the site is ready and you upload it to the server, so it actually starts working. Until then it lives only on the computer of the person who built it - like a draft in a drawer. Once you upload it, it wakes up on that night shift and starts answering people all over the world.
So when you hear "the server is down", it means the night shift has stopped. No one is answering. The site is still there, the files are in place, but the computer that's supposed to serve them isn't working right now.
Is there a soul in it
When I'm building something, deploy is the moment of truth. The design can look flawless on my screen, but until it sits on a server, it exists for no one but me. I don't trust anything until I see it uploaded and running - not in a folder on my laptop.
I keep my own servers. Not because it's fashionable, but because I want to know exactly where everything I make actually lives. The night shift has to be mine, for me to trust it.