Keeping a mailing list current and up to date through different processes, such as correcting and updating the addresses and other data, is referred to as a list maintenance. Businesses deal wit a number of lists, but for them the most important ones are lists of clients and lists of business people. List maintenance is very important in business because it is concerned with keeping information on these mailing lists accurate and up to date. Some names are being added, some are being removed. For some contacts some information may be changed, such as an address or a phone number. This means that list maintenance is an activity which must be performed regularly. There are three types of list maintenance. The first type is called add. This means that any new information is being added to the list. So for example if a new contract is being signed with a client, this contract is added to the list. The second type is is known as remove or delete. This is done in a case where an existing client decides to break of a contract, and no longer wants to be a client of the company, he is being removed from the list. And the third step of list maintenance is called the change. Any information about an existing client that has been change is immediately being changed in the list. These changes can a change in an address, or a change in the company name etc.