SaaS stands for Software as a service. It’s a business model in which you pay for software, such as a blogging application, and the provider maintains the software for you.
In some cases, the software may be provided for free, with a for-cost option also available.
One of the most popular SaaS providers today is WordPress. You can host your blog, or even an entire website, on WordPress for free. For an added cost, you can even use your domain.