In case you use a database-driven script application for your website, all the content that you or the website users add, will be kept in cells and tables in a database, not as simple text in the app files. In contrast, HTML sites are static and all of the content on such a website is part of the actual HTML files. A web-based store app, for instance, takes all the prices, items, user reviews, etc, from its database and this is the same for any other script that allows you to build a dynamic website. The more the info you put, the larger the database becomes, so if you use a script-driven site, you need to make sure that your website hosting plan includes enough database storage space. The latter applies regardless of the kind of databases you will use - for instance MySQL or PostgreSQL.