Matt Mullenweg is an American entrepreneur and web developer best known as the co-founder of WordPress, a popular content management system that powers a significant portion of websites on the internet. He started the project in 2003, which has since grown into a major platform for blogging and website creation. In addition to his work with WordPress, Mullenweg is the CEO of Automattic, the company behind various web services, including WooCommerce and Jetpack. He is an advocate for open-source software and has contributed to the growth of the online community through his efforts in promoting collaboration and innovation.