(What was the earliest version? I know it's lower than 0.2.5.)
(Details needed especially for versions 0.4.x and 0.5.x.)
Also, the default user scripts that were bundled with Greasemonkey by default until this point were removed.
- Edit button in the manage dialog.
- Monkey icon in the status bar, click to enable/disable.
- GM_getValue, GM_setValue
Primarily bugfix release.
May 12th, 2005 
- ".tld" support in @include/@exclude, allowing things like
@include http://www.google.tld/for all international permutations.
- Log level option for GM_log
- Minor enhancements and bugfixes.
Security flaw release. Contained no fixes, rather removed all vulnerable features. Intended for (limited) continued use while fixes were being performed.
The 0.4 branch was an internal development version, where experimentation for security fixes happened.
The first release containing security fixes over 0.3.5 intended for public consumption. "Greasemonkey 0.5 is actually the combination of a massive security audit and all the new code which was planned for 0.4."
- Enhancements to GM_registerMenuCommand: keyboard shortcuts, stability.
- Memory leak fixes.
- "New User Script" menu item, shortcut to a new blank template for user script authors.
- Restricted GM_xmlhttpRequest from accessing local
- Security fix wherein a user script could elevate itself to chrome privileges.
- User can select the editor to use for "Edit" in manage, and "New User Script".
- Unicode support for non-english characters.
September 1st, 2005 
September 12th, 2005 
- Compatibility with Firefox 1.5.
- The Monkey Menu, a context menu for the status bar item added in 0.3 beta.
- Simplified script installation dialogs.
July 28th, 2006 
- Compatibility with Firefox 2.0.
- Foreign language support for Czech, Dutch, and German.
October 16th, 2006 
- Spiffy new installation dialog which more closely resembles the extension installation dialog, and presents more details in a user-friendly way.
- Spanish language support.