Unline Wordpress.com, Blogger or other "free" blogging platforms, Wordpress.org doesn't host websites, so there are no usage policies to worry about. From Wordpress.com you simply download the Wordpress software along with various themes and plugins for installation on your own domain.
Many hosting companies now offer automatic installation of Wordpress through their account control panels, so you don't actually have to download anything from Wordpress.org. Some hosting companies also offer similar "1-click installs" of other blogging and content management systems so you're not limited to using Wordpress.
As daveb1 said, the important part is to host the blog on a domain you own/control. Take regular database backups (in Wordpress, there are plugins that will automate this process for you) and you will be assured of being able to restore all your content in the event anything happens to your blog or the hosting company.