Using free and open source software (FOSS), advocates like to say, is not a popularity contest. It's about doing what's right. However, the Debian and Ubuntu Popularity Contest projects might disagree.
Using the Popularity Contest package, these two projects collect and post weekly anonymous reports about the software used on each system on which theyre installed. The result is a rare insight into the habits of FOSS users, including how often software is upgraded, what applications are used the most, and the differences between the expert-oriented Debian distribution and the more user-friendly Ubuntu distribution.
The main purpose of the project is to collect information for installation, so that the most widely used applications can be put on the first CD of an install set, or installed automatically. In Ubuntu's case, the collected information is also used for software ratings in Add/Remove Software.
Both projects explain that each host data source is identified by a random 128-bit hash, and that identifiers are removed after twenty days. However, those concerned about privacy can choose not to install it, or remove it without any difficulty.
Popularity-contest reports four main statistics for each package: The number of installations, the number of hosts on which the program in the last 30 days (or Votes, as the package calls this statistic), the number of hosts on which the program was not used in the last 30 days (or "Old"), and the number of hosts on which the package was upgraded ("Recent").
Unsurprisingly, core applications that are included in every system, such as dpkg or ncurses log the highest number of installs, and, as often as not, the highest number of Votes and Recent installs as well. The result, as some Ubuntu users complain, is that the popularity ratings in Add/Remove Software are skewed in favor of core applications, and newcomers can be mislead by the relative unpopularity of such useful desktop tools such as Inkscape.
However, if you look at the raw data on the project sites, you can easily ignore core packages and focus on whatever subject interests you.
As you look at last week's figures, one of the most noticeable results is that, in both projects, the number under Votes and Recent are low compared to the number of Installs.
For instance, the Ubuntu results list 425,490 installations of Firefox 3.0, only 92,629 Votes and 63,034 Recent upgrades. In other words, although roughly half of Ubuntu installations reporting include Firefox, only about 20% have used it in the last 30 days, and only 13% have upgraded it.
With IceWeasel, Debian's non-branded version of Firefox, of 46,276 installs, only 25,797 (46%) are recently used, and 11,207 (24%) recently upgraded.
Percentages differ for other packages, but in almost every case, figures for use and upgrading are much lower than for installations. Probably this difference reflects how easy GNU/Linux distributions make the installation of software.
However, what is less obvious is why, when automatic upgrades are available on modern desktops, most people are not upgrading as soon as new packages are detected -- or perhaps not at all. Apparently, the average Ubuntu user and, to a lesser extent, the average Debian user, are far more cautious about upgrades than you would expect from their availability.
Another way you can use the popularity-contest data is as a measure of how comparable software is being used. For example, both Ubuntu and Debian show high numbers of GNOME desktop installations, as you might expect from such GNOME-centered distributions: GNOME is installed on 85% of Ubuntu installations and 50% of Debian installations, and has been used recently by 78% of Ubuntu users and 55% of Debian users.
The relatively low number of Debian users is probably explained by the fact that the distribution appeals to more advanced users than Ubuntu, and such users are more likely to choose one of the dozens of alternative desktops or window managers available, or even to use the command line.
This explanation gains credibility when you find that only one-eighth of Ubuntu users have KDE or Xfce desktops installed, despite the fact that Ubuntu maintains separate sub-distributions called Kubuntu and Xbuntu.
By contrast, the Debian results show only slightly higher percentages of KDE users than the Ubuntu results, and one-sixteenth of Debian installations include Xfce. The Debian results might be abnormally low for KDE if a large number of long-term users participate in popularity-contest, because at one point nine years ago, Debian seriously debated dropping KDE because of licensing issues. However, a more likely explanation is that Debian desktop usage is distributed more widely than Ubuntu's over other alternatives.