2016 turned the world upside down. ɹǝʇʇıʍʇ.com turned twitter upside down.

ɹǝʇʇıʍʇ.com is an example of what is known as an IDN, or internationalized domain name. A node server handles incoming requests, gets the corresponding route on the true twitter site, and injects javascript and CSS in order to flip the site and move the infinite scroll handler to the top of the viewport.

Source: https://github.com/jonathanzong/upside-down-twitter.