GPL isn’t a theme or a plugin. But, It’s a license of the software. The GPL stand for GNU General Public License. It’s free software licenses that gives end user have the ability and freedom to run, study, share, and modify the software. It’s one of a widely use software licensing today, including one of the most popular content management system called WordPress.
In fact, if WordPress doesn’t distribute under this GPL free software license, we may not even heard about it today. Since the WordPress open up the license to give us the ability and freedom of software usage, that we have what we see in the WordPress today. Many years back, WordPress was just a CMS for blogging system only. Today, the WordPress is almost doing everything. You can build POS system with it, build ecommerce site with it and even running your affiliate marketing system with CRM too.
With the power of freedom of using this software, it’s allowed us to do more than you think. It’s also attracted to many great developers actively building themes and plugins to everyone. However, because of the nature of WordPress licensing, all the WordPress Developers forced to publish their themes and plugins under GPL license under WordPress environment.
That’s the reason of cracked themes and plugins are almost everywhere is because those hacker/cracker are doing things in a grey area and abusing the GPL license of WordPress nature. It’s an immoral behavior we shouldn’t support those cracked WordPress theme and plugins site.
To keep WordPress undergrowth healthy under virtuous circle. It’s recommend buying directly from the author to give them a chance to make a living, support their family and survive. When they can survive, they will create more tools that helps your business. You might only enjoy more free tools and service in an affordable price.