Naming your site after your domain may seem obvious to some of you, but you'll be surprised to learn that not every website is named after the domain name even when the webmaster owns that domain name.
Naming a site after its domain name is important, for the simple reason that when people think of your website, they'll think of it by name. If your name is also your URL, they'll automatically know where to go. For example, when people think of thefreecountry.com, they don't have to wonder what URL to type into their browser to get there. The name of the site is also the URL.
Imagine if your business (or website) is called "Acme", but somebody else holds that domain name. Instead, you have some obscure domain name called, say, "mybusiness.com". What happens when your customers, recalling that Acme has a product they want, type ? They'll end up at your competitor's website. One lost sale.