This is the third in a five part series called WordPress Basics.
Nearly every website today is database driven, your WordPress database holds all your text, links, login details and settings for your website. Every page is called up by the website searching your database and then pulls the relevant information for you.
These sites are dynamic in nature as the page is created per visit. To make this go faster, you can cache the most visited pages, the downside of this, is if you update a page that is cached, you will have to clear the cache so that the page must be rebuilt.