Investigate WordPress
Mullenweg is a hypocrite who exploited GPLed code to build a commercial empire using the dirty tricks the GPL was designed to stop.
While WP core may be in the clear, the "freemium" themes/plugins on wordpress.org surely violate the GPL by placing restrictions on GPLed code. Mullenweg has made noises about it (https://ma.tt/2015/07/licenses-going-dutch/) but failed to remove offending plugins from his site. He (Automattic) actually owns some of the worst offenders, like Jetpack. At the very least, they violate the GPL in spirit. His hosted WP service (wordpress.com) may violate GPL as well. There's ample ammunition for Wix to fight back.
I hope they knock each other out cold.
Biting the hand that feeds IT
