There are two standards currently used for most e-mail sent today. SMTP stands for simple mail transfer protocol. POP is an acronym Post Office Protocol. Though it may sound confusing, the difference is not hard to understand. POP is a protocol for storage of email. SMTP is a protocol for sending and receiving.
To give a real-world illustration, SMTP would be like a letter carrier or mailman. He or she can deliver or pick up mail for transfer to another location. POP is like a mailbox or Post Office Box. It is the location the mail is delivered to and where it stays until the recipient is ready to read it. Outgoing mail can also be put in the mailbox.
SMTP is the standard by which the vast majority of mail of transferred on the Internet. Though invented in the early 1980s, it has a reputation for being very reliable. Most mail goes through without problems and gets to the recipient quickly.
However, SMTP also has some shortcomings that were not anticipated when it was first created, and that has created issues for many modern users. SMTP has no way of verifying senders are who they claim they are. Back in the 1980s, when the Internet was used among a select group of people mainly in government and academia, this was not a big issue.
Since the 1990s, it has become a major problem. SMTP’s shortcomings, have given rise not only to spam, but a host of other more malicious enterprises, such as virus transfers. If a program can search an inbox and send a virus as an attachment to everyone on a certain person’s contact list, using that person’s name, it is more likely to be opened by the recipient, who trusts the person they think it is coming from. Though efforts have been made to increase the security of the SMTP standard, it is still a long way from being truly effective.
POP was first designed in 1984 with the idea of allowing users to access an e-mail server, retrieve messages to a local folder located on the computer, and then go offline for reading and writing replies. In part, the offline capabilities were developed at a time when logging on to the Internet was relatively expensive and users were charged per minute. Currently, most of those using the POP standard are using the third version, developed in 1988. This is often referred to as POP3.