Bulk mailing of letters is used for increase in the customer base, for advertizing of different products, for the notification of a large number of people, etc. It is very inexpensive type of advertizing therefore recently it is popular among the large companies and individuals.
Electronic mailing is the fine transmission medium of information for big group of people. If it is issued small circulation, then it is possible to make it directly in an e-mail client. For creation of large mailings use specialized programs.