I just read an interesting, albeit admittedly unscientific, post by Starry Hope on the popularity of Ubuntu.  Here are the two graphs from the post which I found to be the most interesting.

Google Search volume of Ubuntu compared to Debian, Fedora/Red Hat, and openSUSE:

Ubuntu compared to the top ten other Linux distributions combined:

If you think Google search volume is a fair indicator of popularity, than it’s pretty clear that Ubuntu is more popular than all the rest of the Linux distributions put together.

While I think there is good reason for Ubuntu to be so far out in front, I hope that we in the Ubuntu Community don’t let that reality go to our heads, but continue to be good citizens in the greater Linux Community.  While Ubuntu may be the most popular distrubution, Canonical (Ubuntu’s source of paid development) isn’t very profitable (yet?) and depends on the development efforts paid for by the makers of competing distrubutions like Red Hat and Novell to produce much of the software which makes Ubuntu complete.