POP, IMAP, SMTP – What’s The Difference

Liam from Boulder writes:

When you set up e-mail you’ll see POP, SMTP and IMAP and you have to pick what kind of account you want. What’s the difference? What do the letters mean. I asked the tech support guy form my cable company and he didn’t do much but repeat what the names were and tell me their e-mail was SMTP and that if I had a question about Outlook, I needed to ask Microsoft. Is there a simple explanation, a non-techie person could understand.

Sure Liam, let’s go over what it all means.

POP3 – Post Office Protocol 3. This kind of server stores your incoming messages on the server until you use an e-mail client like Windows Mail, Outlook or Thunderbird to download them to your computer.  Generally those messages are then deleted from the server. You can then only access those message on the computer where you’ve downloaded them.

IMAP – Internet Message Access Protocol. This type of server lets you access your e-mail without downloading it to a computer. You can read, edit or delete the messages right on the server. The messages will remain on the server until you choose to delete them. You can access your e-mail from other computers or mobile devices. More and more people are moving to IMAP for the convenience of being able to access their e-mail at any time from any device.

SMTP – Simple Mail Transfer Protocol. This server is only for outgoing e-mail. You can use it with a POP3 or IMAP sever. So if you see an error referring to SMTP – it’s talking about outgoing e-mail.

~ Cynthia

6 thoughts on “POP, IMAP, SMTP – What’s The Difference

  1. The comment re POP3 accounts is a bit misleading. I have used that with e-mail clients (first Outlook, then Thunderbird) and both provided for leaving messages on server for specified periods after the initial download, allowing me to access them from other devices for up to the specified period (in my case, I chose 60 days). That takes away the stated advantage of IMAP. In fact, I have always preferred to keep certain e-mail messages on my computer. That way, I am not dependent on the particular provider keeping my messages safe, especially since I may want to change providers someday.
    The part of your answer devoted to SMTP had typos – twice you referred to it as STMP.

  2. I think that Les is nit picking. Cynthia’s post clearly explains the difference between IMAP and POP3 for incoming mail and tells the reader what SMPT stands for. We all make typos, it is easy to overlook them especially with a name like STMP, excuse me, I meant SMTP. Great piece of work, Cynthia!

  3. Loved the humor in Peter’s reply way back on October 3, 2013. He is correct in Cynthia’s post does clearly explain in very simple terms the basic differences. That was all that the non-techie usually want.

    Glad to see this repeated because I missed it the first time.

  4. The other “Les” made very valid points and the comment about typos was only a very minor after thought by him. I get tired of “experts” saying the difference between POP3 and IMAP is whether the messages get deleted immediately from the server. I also use Outlook POP3 (and have used Thunderbird) and the options for both allow for messages being left on the server for a period the user chooses, so this is NOT an advantage of IMAP. Like the other Les, I prefer to have retained messages kept on my own hard drive rather than rely on the whims of an ISP. (In fact, I don’t use the e-mail provided by my ISP so I can minimize changing e-mail addresses if I change ISPs.) Of course, I also keep my hard drive backed up all the time (Carbonite) so I could restore all my data to another computer if mine fails.

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