Automattic, the company behind WordPress.com, founded by WordPress creator Matt Mullenweg, has been trying, and succeeding in fact, to create a revenue model from blogging.
To date, it's been making money by selling premium features to regular users, such as the ability to customize themes, and by selling a white-label service, WordPress.com VIP to big blogs such as TechCrunch or GigaOM.
Now, it's adding a third tier, WordPress.com Enterprise, a mixture of the two. It comes with all of the premium features available to regular users, as well as some of the perks VIP customers get.
In essence, Enterprise is a top notch hosting service with a hassle-free WordPress install and all the additional themes and plugins you'd want.
It should be particularly popular with companies or people that want to set up a site quickly and have it able to withstand any traffic you can throw at it, which WordPress.com definitely can.