The CPU load depends upon the time a server spends executing a script every time a visitor opens a webpage on a specific script-driven Internet site. Static HTML sites use barely any CPU time, but this isn't the situation with the far more advanced and functional scripts, that use a database and display dynamic content. The more people open such a website, the more load will be generated on the server and if the database is very large, the MySQL server shall be loaded too. An example of what can cause high load is an Internet store with a large number of products. If it's popular, many people will be exploring it simultaneously and if they look for items, the entire database which contains all of the products shall also be continuously accessed by the script, which will result in high load. In this light, having CPU and MySQL load statistics will give you an idea of how the site is doing, if it needs to be optimized or if you simply just need a more effective hosting solution - if the site is popular and the current setup cannot deal with the load.