WordPress

Wordpress is a CMS. A server backed by a database. It is a PHP application. You can download it and run on your our server. Or Wordpress.com provides hosting services where all you need is a Wordpress account and using that account and create however many sites you want. With that you get a dot wordpress url. There are two views. What the admin sees and what visitors see. You have templates and things. You can insert things. There are plugins. Plugins marketplace is big. All some php code that also has access to the database. New and new versions of workpress releases. Since the database is what holds the content, the application can be changes.