The CPU load depends on the length of time a web server spends executing a script each time a visitor opens a webpage on a specific script-driven site. Static HTML Internet sites use hardly any CPU time, but this is not the situation with the much more advanced and functional scripts, which use a database and display dynamic content. The more customers open such a site, the more load will be created on the server and if the database is big, the MySQL server will be loaded also. An example of what can cause high load is a web-based store with a huge number of products. If it's popular, a lot of people shall be browsing it concurrently and if they search for 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 statistics will give you an idea of how the website is doing, if it has to be optimized or if you just need a more potent website hosting solution - if the website is very popular and the existing setup cannot cope with the load.