From this May 2012’s Wired magazine piece How to spot the future. 

Bank on openness: […] the best example may be nearly invisible, even to a dedicated user of the Internet: blogging platforms. Less than a decade ago there were a multitude of services competing for the emerging legion of bloggers: Movable Type, TypePad, Blogger, WordPress. Today, only the last two remain relevant, and of these, the small, scrappy WordPress is the champ. WordPress prevailed for several reasons. For one, it was free and fantastically easy to install, allowing an aspiring blogger (or blogging company) to get off the ground in hours. Users who wanted a more robust design or additional features could turn to a community of fellow users who had created tools to meet their own needs. And that community didn’t just use WordPress—many made money on it by selling their designs and plug-ins. Their investment of time and resources emboldened others, and soon the WordPress community was stronger than any top-down business model forged inside the walls of their competition.