SMF
SMF - Simple Machines Forum - was founded in 2003 after license issues with YABB SE.
The original core development team was Jeff Lewis, Joseph Fung and "[Unknown] W. Brackets", and SMF 1.0 was released in 2004.
More information: https://www.simplemachines.org/
The name
The name was chosen to imply both the fact that it should be simple to use, but also that it was never intended to be only a forum product; the use of 'simple machines' in the plural was to indicate the intent for an ecosystem of which the forum was merely the first.
1.0 release
During the development phase, it was referred to as 'Unknown's secret project', and developed alongside security patches and support for YABB SE but all major development had stopped on YABB SE by early 2003 to make way for SMF.
It debuted in early 2004 for public consumption, featuring an upgrader/importer for YABB SE forums, plus a copy of the stock YABB SE theme (dubbed Classic), and its own new default theme, Babylon.
1.1 release
1.1 was released in autumn 2006 featuring a new default theme (internally referred to as NDT during its development) and later named Core. Both Classic and Babylon themes were shipped with 1.1.
The main development focus in 1.1 was integration support for portals (e.g. a bridge to Mambo/Joomla), though various general improvements were added.
It was around this time that Jeff, Joseph and Unknown began to transition out of the community to focus on other things in their lives.
2.0 release
Several major features were added in 2.0: support for PostgreSQL and SQLite databases, post moderation, built in warning system, paid subscriptions.
However, there was a lot of internal debate within the team especially during 2009-2010 and the project changed management as well as license; the 2.0 release was finally made in 2011 under the BSD license.
2.0 also debuted with another new theme, Curve, and Core was also shipped with it. Classic and Babylon ports for 2.0 were later made.
2.1 release
After much internal tension, 2.1 was finally released in 2022, nearly 11 years after the previous release (though the team had continued to make security and maintenance releases in that time for the 2.0 branch).
2.1 ships with a number of modern features: responsive theme by default (dubbed Curve2), likes, mentions, alerts, redesigned admin panel, post and PM drafts, a new WYSIWYG editor, better support for Unicode.
SQLite support, as well as support for admin panel backups were dropped due to a lack of reliability, and minor other options were dropped, much to the community's displeasure.
3.0 release
A 3.0 release is in the works.
Forks
Several forks were made from SMF after the license was updated.
