Perpetual, worldwide, royalty-free
The OGL was embraced by fans and creators because it allowed them to benefit from D&D’s intellectual property, and because of the protections the license gave them. The OGL 1.0a grants “perpetual, worldwide, royalty-free” usage of the SRD, which means that you don’t have to pay WOTC to use the license, and you don’t have to pay Wizards any royalties on revenue brought in on products that use the SRD.
It protected fans from getting sued by the company, but it also allowed the company to enjoy the popularity brought on by thousands of creators using the SRD as a base and writing games specifically for their product. Over the past decade, this network effect helped the fifth edition of the game gain popularity and help Dungeons & Dragons attain unprecedented mass appeal.
