[4][5][6] Boodman was inspired to write Greasemonkey after looking at a Firefox extension designed to clean up the interface of AllMusic,[7] written by Adrian Holovaty, who later became a userscript developer.

[10] During this time, a Greasemonkey compiler was also developed for converting a userscript into a standalone Firefox extension.

To accommodate the growing number of scripts, userscripts.org was founded by Britt Selvitelle and other members of the Greasemonkey community in late 2005.

In 2010, the last known admin Jesse Andrews posted that the site was in maintenance mode due to lack of time and asked for a new maintainer to volunteer.

Over the following year spam scripts became more common, server downtime increased and the install count bug remained.

[16] Greasemonkey user scripts are written in JavaScript and manipulate the contents of a web page using the Document Object Model interface.

Compared to writing a full-fledged Firefox extension, user scripting is a very modest step up in complexity from basic web programming.

File hosting servers for Greasemonkey require that the URLs for the scripts end with .user.js and not with a MIME type like text/html.