[h=2]But I thought it was unlimited?[/h]Depending on the type of plan you have, certain things on your account are indeed unlimited. For example, shared accounts give unlimited disk space and bandwidth. When companies say unlimited, what they mean is that they do not meter or limit you on that item. But just because you can have an unlimited amount of something does not mean it is physically possible to consume an infinite amount. Unlimited does not mean infinite.
For example, when you go to an all-you-can-eat buffet, you can eat an unlimited amount of food. However, it is impossible for you to eat an infinite amount of food because of the size of your stomach, the number of hours the restaurant is open, how much food is physically available, and the fact that you cannot share your food or take it home with you. Certain rules for the buffet are put in place so one person does not come in and take all the food from all the other paying customers.
Similarly, it is not possible to use an infinite amount of the server since there are other limits in place, like how much CPU you can use at one time, how many processes you can have open at one time, how many emails you can send out in an hour, etc. Certain rules are in place to make sure one person does not use the entire server on a shared account, preventing other customers from using the server.