Traditional shared hosting environments have no control over individual customers in the event of a resource spike. If one customer suddenly experiences a big resource spike from a large amount of traffic, poorly written script, or a denial of service attack, all the other customers on the server are slowed or brought down.
CloudLinux isolates each customer at the kernel level so that no matter what, the customer can never exceed the resources allocated to them. During a sudden resource spike all other customers are left unaffected!
For more information, see our article "What is LVE?"