What are POP and IMAP?
When you receive E-mail through the App on your phone or mail client (Microsoft Outlook, for example) odds are that you are already using POP or IMAP to do it. POP and IMAP are protocols, or rules, which control how devices and applications receive mail.
You don't need to know the ins and outs of how it works because it's all done for you in the background. What you do need to know is what the key differences between POP and IMAP are and why it matters to you.
Post Office Protocol (POP)
- Advantages: Local storage reduces importance of account size limits and keeps copies of your mail until deleted.
- Disadvantages: Can be difficult to manage across multiple devices.
POP has been around since E-mail first arrived on the scene in earnest in the mid '90s. Unless your E-mail account was a company account stored on their network, the odds are that, if you had an E-mail account at this time, it was a POP account. If an E-mail was sent to firstname.lastname@example.org it would arrive at the mail server (this is the internet server that sends, receives and organises your mail, sort of like a post office) at ekmtest.com and wait until you opened your mail application to retrieve it. Depending on the settings of your mail client, the mail would then be deleted from the server or allowed to remain for a certain period of time, often 14 days.
Once downloaded from the server, the mail would always be accessible on the computer it was downloaded to. This is still useful today, but it was crucial the early days of E-mail when access to the internet was often sparce. Once you had your mail downloaded to your computer, you always had access to it, and this is still true today. With internet access being more readily available, it's less of a priority to have mail saved to your computer or mobile device, especially if that device doesn't have much storage space. It does make mailbox size less of a concern, however, as even mobile devices can have larger storage capacities than some mail services.
POP can make managing E-mail from the same account across multiple devices risky, as its first instinct is to download the mail and remove it from the server. Mail can be left on the server if instructed so that others can access it, but all it takes is one device to connect without this setting and all of the mail will be deleted once it has been downloaded.
Instant Messaging Access Protocal (IMAP)
- Advantages: Access E-mail from anywhere from any device. Access from multiple devices at the same time.
- Disadvantages: Requires an internet connection to view most E-mail in your mailbox. Storage on the server may be subject to limits.
While you may have only heard of IMAP in the last few years, IMAP actually originated in 1986 as an alternative to POP. So, why are we only hearing so much about it recently? IMAP had two main drawbacks during the '90s; The first is that it's much more dependent on an easily-accessible internet connect for it to be used to it's full potential. The second is that, because IMAP-based E-mail remains on the mailserver instead of being downloaded to a mail client or device like POP does, it was potentially prohibitive to mail providers to keep large amounts of E-mail on their own servers, as would have been the case.
Mobile devices are among the main reasons that IMAP's popularity has increased. Allowing greater ability to connect to the internet over wireless or mobile broadband connections made IMAP a more viable choice, especially as IMAP could be used on the device without causing issues with any existing POP or IMAP accounts. Cheaper storage costs and the introduction of the 'cloud storage' concept made it much cheaper and attractive to store E-mail and other data in 'the cloud' (or on a mailserver) as this way it is accessible from anywhere and won't be lost if a PC or device has a problem or is lost/stolen.