Using Alexa, a traffic ranking service from Amazon, I compared drupal.org's traffic with the traffic of other Free and Open Source content management systems' websites. The term content management system is used broadly here as the list of projects include phpBB, Plone, TikiWiki, Wordpress, Xoops, Mambo, PHP-Nuke, PostNuke, Typo3, Xaraya and Drupal friend CivicSpace.

Popularity is compared based on Alexa's daily reach-metric, which measures the number of users. Here, foo.com and www.foo.com are treated as the same site because they reside on the same domain. The results are presented in pretty graphs (generated by Alexa) and included below. Of course, the results must be taken with a grain of salt as the popularity of a product's website is not necessarily related to the popularity of the product itself, or the quality thereof. So whenever I write popularity that really means the popularity of the website as measured by Alexa. Regardless, a number of interesting observations can be made ...

1. The popularity of most Free and Open Source CMS tools is in an upward trend. This implies that more and more people start using a Free or Open Source CMS to manage their website. The fact there is a clear correlation between the various growth curves (eg. most graphs show a dip in the summer of 2004) supports this observation.
2. With a daily reach of 500M users, phpBB is by far the most popular community platform.
3. phpBB, Xoops, Wordpress, Mambo and PHP-Nuke are more popular than Drupal. Plone, TikiWiki, Typo3 and Xaraya are less popular than Drupal.
4. Drupal, Typo3, Xoops and Plone have comparable growth rates while Mambo and Wordpress are growing notably faster. Mambo and Wordpress have about the same popularity (i.e. a daily reach towards 300M users), yet Wordpress' growth is much more aggressive so it won't take long until Wordpress is much more popular than Mambo. Clearly, Wordpress is hot! Notable exceptions are PHP-Nuke and two of its derivatives, PostNuke and Xaraya, who have been steadily losing popularity over the past year.
5. Drupal.org's daily reach doubled since the beginning of 2005. This might be a natural compensation for the fact we did not appear to grow much in 2004. The fact we had performance issues might have had something to do with that. At the same time, CivicSpace, a Drupal distribution, is slowly gaining popularity too. As Drupal is growing faster than CivicSpace is, closer integration is likely to be beneficial.

(Tease: we plan to make some changes to drupal.org to accommodate Drupal's growth.)

Drupal versus phpBB

Drupal versus Plone

Drupal versus TikiWiki

Drupal versus Wordpress

Drupal versus Xoops

Drupal versus Mambo

Drupal versus PHP-Nuke

Drupal versus PostNuke

Drupal versus Typo3

Drupal versus Xaraya

Drupal versus CivicSpace