I'd like to keep a talk about the architecture and challenges of the Hildon desktop in Maemo 5, currently in alpha stage. That includes a Matchbox Window Manager 2 and Clutter based compositing window manager (aka. hildon-desktop), using EGL and OpenGL ES 2.0 for drawing and animations, task launcher for starting applications, task switcher for switching between applications, home (or desktop) applets, status area and plugins. We are using the Xorg X window system and a Maemo/Debian based GNU/Linux operating system (more open-source community projects we depend on at http://wiki.maemo.org/Task:Upstream_projects). Our applications are based on Hildon GTK+ widgets and the GTK+ toolkit.
Author bio: Nokia
Kimmo Hämäläinen works as the architect of UI Framework for the Fremantle Maemo (http://maemo.org) release in Maemo Software / Nokia. The UI Framework includes the Hildon desktop on a Nokia mobile device.