X.org is an evolution from the XFree86 project, that became the widely accepted "reference" implementation in 2004. X.org improves upon XFree86 in terms of the way the project is coordinated, the way the codebase is organised and the approach to graphics acceleration.

The X.org team is hard at work on a new Acceleration Architecture, as well as the inclusion of a variety of exciting new X features such as window composition (which allows for sexy transparency effects).