The CPU load depends on the time period a web server spends executing a script each time a visitor opens a webpage on a particular script-driven website. Static HTML sites use hardly any CPU time, but it's not the situation with the significantly more sophisticated and functional scripts, which use a database and display dynamic content. The more clients open this type of a site, 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 could cause high load is an online store with a large number of products. If it's popular, lots of people will be exploring it concurrently and if they search for items, the entire database which 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 stats can provide an idea of how the website is doing, if it has to be optimized or if you simply need a more effective web hosting solution - if the site is very popular and the current setup cannot handle the load.