The CPU load is dependent upon the time period a server spends executing a script each time a visitor opens a webpage on a certain script-driven site. Static HTML Internet sites use barely any CPU time, but it is not so with the considerably more complex and functional scripts, which use a database and display dynamic content. The more people open this type of a website, the more load shall be created on the hosting server and if the database is large, the MySQL server shall be loaded too. A good example of what can cause high load is an online store with a large number of products. If it's popular, a lot of people shall be browsing it at the same time and if they seek out items, the entire database that contains all the products will also be continuously accessed by the script, which will result in high load. In this light, having CPU and MySQL load data will provide you with an idea of how the site is doing, if it needs to be optimized or if you just need a more powerful hosting solution - if the website is very popular and the established setup can't handle the load.