While it may appear like it's designed just for blogs, WordPress can be used to design complete websites. It's particularly attractive to small businesses because of the ease of use and high amount of customization that it brings.
To harness the full potential of WordPress, you need to understand how to develop plugins for it. These will allow you to create everything from simple word replacement filters to entire applications that make it
possible to turn your WordPress website into something with a social media-like functionality.
The problem is that WordPress plugin development from scratch can be particularly obtuse to people whom aren't used to the way that WordPress works. Phil Derksen's exhaustive tutorial on developing a simple WordPress plugin from scratch makes this process particularly more accessible for first-time plugin developers.
If you don't think that you need to educate yourself in WordPress plugin development, then think again. The prevalence of WordPress creates numerous business-to-business opportunities for plugin development while learning how to develop a plugin will greatly enhance your understanding of how WordPress's core works.
This can be enough to begin developing your own massive products or to simply learn enough to add that tiny feature your WordPress website has always lacked. You will definitely benefit from perusing through this plugin tutorial and reading some of the resources that Phil has taken the time to list.