Let's say you are an ordinary developer, not a wizard at administrating the Apache server. You are looking for a place to host your side project, a Flask application (Flask is a Python web framework). To have the most control at only a small price, you provision a cloud server at your friendly cloud hosting company (Dreamhost, in my case). Perhaps you were not satisfied with free hosting sites, because they give you so little computing power that you quickly max out your available database connections. And so you decide to run it on your own server.
Just to be clear, this article does not deal with production-caliber Flask applications. It describes a minimal, very basic deployment options for simple applications such as your side projects or hobby projects. It does not address, for example, Python virtualenv. Maybe in the future.