Each time a visitor opens your website, the web browser sends a request to the server, which in turn executes it and gives the necessary data as a response. A basic HTML website uses very little resources as it's static, but database-driven platforms are more demanding and use much more processing time. Each and every page that is served generates two sorts of load - CPU load, that depends on the length of time the hosting server spends executing a certain script; and MySQL load, which depends on the number of database queries produced by the script while the end user browses the site. Higher load will be produced if many people surf a given website at the same time or if numerous database calls are made at the same time. Two good examples are a discussion board with many users or an online store in which a client enters a term within a search box and thousands of items are searched. Having thorough stats about the load which your Internet site generates will help you optimize the content or see if it is time for you to switch to a more powerful type of web hosting service, if the site is simply getting really popular.