In my book, Platform: Get Noticed in a Noisy World, I recommend you start blogging with WordPress.com. It’s free and easy to get started. But if you are serious about blogging, you will eventually want to upgrade to self-hosted WordPress, also known as WordPress.org.
What’s the difference? WordPress.com is the hosted version of WordPress. In other words, the software lives on Automattic’s servers. They are the parent company of WordPress.