Breaking news
Compiz and Compiz Fusion are merging and are now known as Compiz.
As an immediate consequence, most Compiz Fusion websites are going to be moved in the upcoming days and weeks. Stay aware !
What is Compiz Fusion ?
(taken from AboutCompizFusion Wiki page)
Compiz Fusion is the result of a merge between the well-known Beryl composite window manager and Compiz Extras, a community set of improvements to the Compiz composite window manager. Compiz Fusion aims to provide an easy and fun-to-use windowed environment, allowing use of the graphics hardware to render each individual window and the entire screen, to provide some impressive effects, speed and usefulness. The first Compiz Fusion developer release was Compiz Fusion 0.5.2 on August 13th, shortly after Compiz 0.5.2 was released. First stable release of Compiz Fusion is 0.6.0 released on October 20.
Compiz Fusion is an open-source software project, meaning anyone can use it freely and contribute.
It is important to note that Compiz and Compiz Fusion are not the same thing (see: Compiz Fusion Vs Compiz). There is close co-operation between the developers of Compiz and the developers of Compiz Fusion, though ; in fact, many Compiz Fusion developers are also Compiz developers.