The CPU load depends upon the time a web server spends executing a script when a visitor opens a page on a particular script-driven website. Static HTML sites use barely any CPU time, but this isn't so with the considerably more sophisticated and functional scripts, that use a database and display dynamic content. The more people open this kind of an Internet site, the more load shall be produced on the server and if the database is very large, the MySQL server will be loaded also. An illustration of what may cause high load is a web-based store with thousands of products. If it's popular, a lot of people shall be visiting it simultaneously and if they look for items, the entire database that contains all of the products will also be frequently accessed by the script, which will result in high load. In this light, having CPU and MySQL load data can provide an idea of how the website is doing, if it needs to be optimized or if you just need a more efficient website hosting solution - if the site is extremely popular and the established setup cannot handle the load.