Portfolio websites are sites that showing examples of past work.
Service providers who want to show their clients the quality of the work they provide can use a portfolio website to collect some of the best samples of past work they have done. This type of website is simpler to build than a business website and more focused on a particular tasks collecting work samples.
This type of website is most common for creative professionals and freelancers that are hired based on demonstrated skills and can be a more efficient alternative to a business website that serves a similar focus.