The CPU load depends on the amount of time a server spends executing a script when a visitor opens a page on a particular script-driven site. Static HTML sites use hardly any CPU time, but this isn't the case with the considerably more complex and functional scripts, which use a database and display dynamic content. The more individuals open this type of an Internet site, the more load shall be created on the server and if the database is very large, the MySQL server will be loaded as well. An illustration of what can cause high load is an online store with tens of thousands of products. If it's popular, plenty of people will be visiting it all at once and if they seek out items, the whole database which contains all of the products will also be constantly accessed by the script, which will result in high load. In this light, having CPU and MySQL load data will give you an idea of how the website is doing, if it needs to be optimized or if you just need a more powerful web hosting solution - if the website is really popular and the existing setup can't cope with the load.