A lot of Flickr users probably wonder why they see file extensions of ".gne" in Flickr URLs while browsing the website. An example below:

Unlike .html, .php, .pl, and other file extensions, there is no programming language associated with .gne. Before being acquired by Yahoo, Flickr was created and maintained by Ludicorp. Ludicorp's main project was a massively multiplayer computer game called Game Never Ending. The Wikipedia article on Game Never Ending states that,

Although development of the game was later cancelled, the tools built for GNE later evolved into Flickr, a widely-hailed photo-sharing service. Occasional signs of this legacy are visible, such as the '.gne' file extension appearing in Flickr's URLs.

Flickr was originally meant to be a set of tools for a computer game, but the game faded away while Flickr has exploded into one of the most cited examples of Web 2.0.