According to a
recent W3Techs survey, Debian has just surpassed CentOS to become the
most popular GNU/Linux distribution on web servers.
The survey is based on the analysis of the top million web sites
according to Alexa, in order to select a representative sample of
established sites, and focused only on the technologies used for web sites (and
not individual web pages or desktop installations).
In fact, at the beginning of 2012, Debian was used by 29.4% of all
Linux-based sites (and by 9.7% of all web sites), while CentOS was used
by 29.1% of all Linux-based sites (and by 9.5% of all web sites).
Debian "is also the fastest growing operating system at the moment: every
day 54 of the top 1 million sites switch to Debian", said Matthias
Gelbmann in the article.
With regard to the geographical distribution of web sites using Debian, the
most are in Europe (with 39.7% of all sites in Germany, 36.1% in
Poland, 33.6% in France and 26.4% in Russia).