In order to understand things it is good to look beyond the surface. Ubuntu Mobile is a great neighbor for Maemo, as it is the Moblin project, GNOME, freedesktop.org, Debian, etc. There is also a % of merit for RedHat and the OLPC project, and ultimately everybody involved in the pieces that sustain Ubuntu Mobile just as they sustain Maemo.

Each of these projects concentrates on some aspects, has some strengths and some weaknesses. Canonical knows how to integrate openly and bring user excitement. They do this really well.

Nokia knows how to contribute in the areas of the Linux desktop that need improvement in order to be efficient in the mobile context. I think Nokia does this well, so well that most of you don't even notice.

All the projects above have benfited from that, and Nokia benefits in one way or another from all the projects above. The beauty of free software.

http://packages.ubuntu.com/hardy/ubuntu-mobile

If you have the patience to check the packages and its copyrights you will see Nokia directly active in essential pieces e.g. Hildon and Sapwood. It is also involved in projects essential also for the desktop like GStreamer, D-Bus or BlueZ. And has an important role supporting the development of Matchbox and other components by other companies.

This and the excellent post of JohnX above should give you a more accurate idea of what is going on.