This is one of my favorite questions people ask. The answer is pretty much infinite.
WordPress can be used in so many ways. Whether you need a standard blog platform or an easy way to do an old fashioned website, WordPress can deliver. Between the wealth of WordPress Themes, Plugins and Widgets available you can mix and match the tools to quickly create a website or blog. It is also a great way to Park a domain while you are developing the site, you can setup a home page, with enough information to get indexed in the search engines so that when the site goes live it is already indexed for the main topic.
And to clarify, I am talking about self hosted WordPress, not hosting on WordPress.com. Using WordPress.com to host a blog is certainly an easy way to get started. Personally I just can not see giving away an opportunity to build your own site and credibility in the search engines and social networks. Yes, that means there is a cost, but the cost is so low these days, if you are gonna step out and create something, make it yours.
Here a few links to tutorials and information on How To Use WordPress.