Read:
http://codingexperiments.com/archives/149
the article use Google Trend to measure, during the period 2004 - 2008.
the article quotes this guy's theory "On the Web, If You're Not
Growing, You're Dying"
http://www.louisgray.com/live/2008/06/on-web-if-youre-not-growing-youre-dying.html
it shows Debian, Redhat, Fedora, Suse, OpenSuse,
Slackware declining.
but Ubuntu grows a lot.
the last graph shows the term ubuntu has become almost as
popular as Linux.
I did a Google Trend search with all of these "debian, redhat, fedora,
slackware, suse, opensuse , ubuntu"
http://www.google.com/trends?q=debian%2C+redhat%2C+fedora%2C+slackware%2C+suse%2C+opensuse+%2C+ubuntu&ctab=0&geo=all&date=all&sort=1
but Google Trend seems to have limitation of 5 terms.
In India (at least per Google Trends), Red hat and Fedora rules.
http://www.google.com/trends?q=debian%2C+redhat%2C+ubuntu%2C+fedora%2C+suse&ctab=0&geo=all&date=all&sort=1
benjamin rualthanzauva