DirectFB is a thin library that provides developers with hardware graphics acceleration, input device handling and abstraction, an integrated windowing system with support for translucent windows and multiple display layers on top of the Linux framebuffer device. It is a complete hardware abstraction layer with software fallbacks for every graphics operation that is not supported by the underlying hardware.
Smitten differs from traditional media centres in three major ways. It contains no media playback at all, which makes it very small (and suitable for porting to embedded systems) and quick to initialize. It targets a TV display and interface, which means there's less information on any particular screen, and a much simpler control interface consisting of left, right, up, down, and select. No mouse is required. It is also highly skinnable, and cross-platform to most systems. Essentially, it provides an easy-to-use menu system that allows the user to navigate a hierarchy of files, and view them using an (external) tool.