Greeter just says displays a web page that says hello. It is intended for educational purposes, particularly in order to teach people about how you deploy Django apps. For example, I have used it in a deployment webinar.
By default it says "Hello, world!" and shows a default image. It also has a database table (a Django model) of "greetees" which can be edited with the Django Admin. If the table is nonempty, instead of greeting the world the app picks up a greetee at random from the table, and shows their image.
If the setting GREETER_LOG is True (by default it's False), then each visit is logged in the database table VisitorLog (viewable through the admin). You would never do this in a serious app; it's just a way to have the app write to the database on each request in order to experiment with how much this affects the number of requests it can serve.
© 2017 Antonis Christofides
To the extent possible under law, I hereby waive all copyright and related or neighboring rights to Greeter.