First, I compared WordPress to what I figure is its most direct competitor: Movable Type. Since 2004, WordPress has skyrocketed in search volume, while a gradual decline is visible for Movable Type:
(blue is WordPress, red is Movable Type
Then I decided to see how WordPress is measuring up to another Open Source software that’s been around for a long time: Joomla. Here’s the surprise: Joomla is way up over WordPress in search volume!
Do these results mean anything? Could this be suggesting that Joomla is primed to be the next favorite Open Source software, or that it already is?