[pbhjpbhj]

Not being familiar with the subject basically it seems that:

Docker is a simple description of an internet server including the various services required (mysql, httpd, sshd, etc. - the bundle being call a deck).

It seems then you can create a server elsewhere (eg on your localhost), generate the docker description of that and use that description to fire up a server (either a VM or dedicated) using the service in the OP.

Am I close?

Could I use this to do general web hosting?

Edit: and looking at digitalocean.com it appears I can activate and deactivate the "server" at will, so I can have it online for an hour for testing and pay < 1¢?