Since then, the WordPress community has flourished and the founders and maintainers have been highly successful in the consulting business. There are vast numbers of great plugins that extend the functionality of the platform. There are numerous well-designed themes available for use. And the platform has certainly expanded to the point that it qualifies as a full-blown content management system.
I use WordPress as the platform for most of the sites I develop. It allows me to offer a client tremendous ease-of-use on the backend. The administrator of a site can add articles and pages, links and events, and (with proper plugin support) operate a variety of niche sites including ecommerce applications.
WordPress is actually six years old today, but with millions using and supporting it, it seems much longer. And in the world of web development, things move in dog years, so happy 42nd birthday (in internet years), WordPress!