GNOME's release history::

• 1999-03-03 - GNOME 1.0 released
• 2000-05-25 - GNOME 1.2 "Bongo GNOME" Unleashed
• 2001-01-24 - China's RedFlag Software Company joins GNOME Foundation
• 2001-04-02 - GNOME 1.4 Power, Stability, Polish and Integration
• 2002-06-26 - GNOME 2.0 Desktop and Developer Platform Released
• 2003-02-05 - GNOME 2.2 improved usability, new utilities and applications
• 2004-09-15 - GNOME 2.8 - usability, speed, internationalization
• 2005-03-09 - GNOME 2.10
• 2005-09-07 - GNOME 2.12
• 2006-04-05 - GNOME 2.14
• 2007-03-14 - GNOME 2.18 released with incremental improvements [* NOTE - the numbering scheme has goes sequentially from a .1 release to a .99 release, thus 2.8 is older than 2.18]

GTK's release history :

• 1998-01-11 - GTK+ 2.0 "The huge feature set of GTK+ 2.0 more than doubles the size of GTK+ 1.2, moving from 230,000 lines of code to 620,000 lines of code. Over the last three years, a line of code was added to GTK+ every 5 minutes. The most important changes include support for a full 32-bit coordinate space, double buffering, antialiased fonts, full Unicode support, new text and tree widgets, and the inclusion of gdk-pixbuf." [source]
• 2002-12-22 - GTK+ 2.2
• 2004-03-16 - GTK+ 2.4
• 2004-12-16 - GTK+ 2.6
• 2005-08-13 - GTK+ 2.8 includes and relies on Cairo
• 2006-07-03 - GTK+ 2.10

de Icaza observed: "Historically, the most painful part of building Gnome applications was the drawing layer ... With Cairo all of these problems will become history." [see source] As GNOME and GTK+ were developing, there was an external project - partly funded by Red Hat - that was develpoing to advance the vector graphics possible.

Cairo's release history::

• 2007-03-19: cairo 1.4.2 release available
• 2007-03-06: cairo 1.4.0 release available
• 2006-11-02: cairo 1.2.6 release available
• 2006-08-18: cairo 1.2.4 release available
• 2006-08-08: cairo 1.2.2 release available
• 2006-07-01: cairo 1.2.0 release available
• 2006-03-15: cairo 1.0.4 released
• 2005-10-03: cairo 1.0.2 released
• 2005-08-24: cairo 1.0.0 released

The 2.18 version of GNOME2 appeared on 3/14/2007. According to its website, this is "the latest version of the popular, multi-platform free desktop environment, providing all the tools a user needs for everyday work, and a platform for developers to write new software."