The E-mail setting consists of a lot of acronyms, and they are: HTTP, POP3, SMTP, IMAP, among others. What does it mean and how much should the user worry about it? Usually there won’t be any choice of server types in the system. The ISP will hold up for either IMAP or POP3 for the incoming mail, and for the outgoing mail it will use SMTP. The meaning of these terms is given below.