If you receive a great deal of email, you might want to consider using a mail filter. In this type of program delivery, messages are delivered to the filtering program as they arrive. The mail filter scans each message to determine into which of several mailboxes it should be put, and then delivers it there. An automatic filter can usually sort messages based on the sender or the topic of the message. Program delivery can also be used as an email file server.
Some sites have a lot of information that they wish to make publicly available.
Many people, however, have only email access to the Internet and can't benefit from such services. You can make files available to these people with a file server that can send documents in response to received email requests. A program that acquires root permissions when it is run. Such programs need more permissions than those of the user who executes them to perform certain tasks. The Unix user for whom a command is executed.