Websites can be considered a lot of things; Brochure, Commerce, Information Desk, Portal or All of the Above!
Some businesses only create a Brochure about their business online.
Others do business online that is commonly referred to as eCommerce.
There are even some businesses that have Question & Answer with Live and Artificial Attendants to service the customer.
Sometimes a website is used only for employees, customers, members or limited-access as a Portal.
Finally, elaborate websites mix all of these services.