WordPress is an Open Source project, which means there are hundreds of people all over the world working on it. (More than most commercial platforms.) It also means you are free to use it for anything from your recipe site to a Fortune 500 web site without paying anyone a license fee and a number of other important freedoms.
About WordPress.org
On this site you can download and install a software script called WordPress. To do this you need a web host who meets the minimum requirements and a little time. WordPress is completely customizable and can be used for almost anything. There is also a service called WordPress.com which lets you get started with a new and free WordPress-based blog in seconds, but varies in several ways and is less flexible than the WordPress you download and install yourself.
What You Can Use WordPress For
WordPress started as just a blogging system, but has evolved to be used as full content management system and so much more through the thousands of plugins and widgets and themes, WordPress is limited only by your imagination. (And tech chops.)