Namely, xf86-video-nouveau 1.0.2 hooks into the platform bus support, support for shared pixmaps with its EXA acceleration back-end, pixmap tracking/updating support, DRI2 offloading support, and the RandR provider/capabilities support. These features are what's being done to work towards Linux support for GPU hot-plugging and NVIDIA Optimus.
There's already been a released Intel driver to take advantage of these new server features while for the Radeon driver the changes are living in Git without a released driver for now. The necessary PRIME import/export support has also landed in libdrm.
Besides the commits by David Airlie for hooking into the new xorg-server capabilities, there's also a fix in this latest Nouveau DDX for shaders on big-endian machines. Additionally, the NVIDIA Fermi "NVC0" and Kepler "NVE0" graphics cards can now take advantage of sync-to-vblank with Nouveau assuming the Linux kernel release is new enough.
The xf86-video-nouveau 1.0.2 release announcement can be found on the project's mailing list.