4ChErN is a single-board version of 4chan, with its name being a parody based on the "ermahgerd" meme. It's based on the same principals - threads, images, anons, and mods.
It is very rudimentary and has a gaping cookie vulnerability. Oops.
Database parameters are set in Database.class.php
The Database module came from http://kjventura.com/2011/11/kickass-php-database-class-for-simple-web-apps/
Sessions are managed very crudely - with a browser cookie that merely hold your username. If you login as one user, you can edit your browser cookie to give you the identity of another user, regardless of whether the user actually exists.
Inputs are sanitized against SQL injections, however HTML is acceptable. Users can include any HTML and it will be displayed. Sad times.