Unlike a static HTML Internet site where all content is on the actual website pages, any script-driven website collects all its info inside a database. Just a couple of examples of this type of websites are a WordPress blog or an OpenCart e-commerce portal - in both cases, item listings, rates, blog posts, user feedback and so on are stored in the database and not inside the actual script files. The more the content you add, the larger the database gets and if your web hosting package has some limit for the maximum size a database may have, your website may not perform properly after you hit that limit. The end results can vary from being unable to add new info to badly working Internet site or even the site displaying only error messages and not being available at all.