WordPress is a free and open source blogging tool and a content management system (CMS) that is a great option for internet marketing. These are my recommendations for plugins, themes and training on how to use it effectively.
Share Your Own "News" with a Blog. Get an overview of what a blog is and how it has changed the way we share "news". However, we do recommend you use a self-installed version of WordPress, not WordPress.com as the video mentions if you are going to be blogging for business.
Expand Your Business with a Membership Website Create Your Membership Model We recommend these sources for giving great overviews of what your business can do with a membership site. 21 membership questions & answers 10 membership models.