In April 2005, with the 5.10 release, Ubuntu gained suspend and hibernate support and an update manager. (Yes, hard as it may be to imagine, such basic functionality was once not part of Ubuntu.)

In June 2006, Canonical introduced the first longterm support (LTS) version of Ubuntu, 6.06. Since LTS releases offer a longer lifecycle—at the time, three years of support for desktop users and five on servers (it is now five years on all types of systems)—this was an important step in making Ubuntu a viable platform for production environments.

The open source KVM virtualization hypervisor became part of Ubuntu with the 7.04 release in April 2007, helping to make Ubuntu a stronger contender as a virtualization—and, eventually, cloud—platform.

The Ubuntu Software Center, which Canonical originally tried to call the Software Store, to the consternation of many users, became part of Ubuntu with version 9.10 in October 2009.

In April 2011, one of the biggest changes to the face of Ubuntu came when Canonical made its home-grown Unity desktop environment the default for Ubuntu 11.04, replacing GNOME. That set the stage for the forays onto new types of devices that remain a central part of Canonical’s strategy today.

The 11.04 release also introduced official support for OpenStack, the massively popular open source cloud platform that remains a key part of Canonical’s strategy today.

Last but not least, the 13.04 release later this week will be the first one that, as Mark Shuttleworth put it in the fall, presents Ubuntu “through a mobile lens.” It also marks a switch to what is essentially a rolling-release cycle for Ubuntu: Instead of the 18 months of support that all previous non-LTS releases offered, 13.04 will receive only nine, the idea being that users who want the very latest software should upgrade constantly. Everyone else can stick to the LTS releases that appear every other year and which will continue to have five-year lifecycles.