All too often, a patron will come in to the library and ask questions related to their email. With the proliferation of mobile devices, laptops, and the ability to access email from remote locations (ex. hotel, library, public computers), patrons are excited to access their email from more than one location. This excitement, however, does come with hesitation considering the unknown. This unknown is whether their emails are synchronized across their devices, computers and on the web, and if not, WHY?
Common email service providers in our area like Comcast/Cox, Frontier/Epix, Gmail and Yahoo! provide several ways to access email stored on their servers besides logging in via their website.
When you want to read email using an app on your personal device, the communication with the main email server is using one of two protocols — IMAP or POP3.
POP3 is slightly older but IMAP is "ALMOST always" a better choice because it provides better, more intuitive synchronization. I say ALMOST due to the fact that there are differing opinions. IMAP also handles larger mailboxes and serves the user better when accessing email from multiple mail client applications (ex. provider web-based, Apple mail, Windows mail, Outlook, Android default mail, myMail, Aqua Mail, Blue Mail, Email by Edison, etc.)
The main difference, however, is that IMAP is used to download, read and manage emails, while POP3 is used ONLY for downloading emails. With IMAP your inbox, sent, and customized folders look alike, and have the same content, whether you’re checking mail on your phone, tablet, or PC. Technically speaking, the servers operated by your email service provider retains the master copy and all devices and apps that are configured for the email account sync with their server(s). Any changes (such as deleting mail) made on one device are automatically reflected in any other app or device syncing to the same account.
With POP3, there is no such synchronization. You can download all email to your device(s) and choose to either delete the copy on the main server(s) or retain it. Any changes made locally on the device (such as read/unread status, deletions) are not communicated back to the main server. In short, each device downloading email has its own standalone copy of all email when using the POP3 protocol. I have read some articles that refer to POP3 as a "dumb" download.
So... Your probably asking yourself if your email is IMAP or POP3. If you get your email from a web site, it's IMAP. If you download it to a mail client without using a web browser, it's probably POP3. Having said that, some email providers (ex. Gmail) do support both IMAP and POP3 protocols.
Double backing to the "ALMOST always a better choice" comment, the individuals that are proponents of POP3 are those who have the following in mind: a) downloading and wiping data off the main servers helps them stay under any storage quota that may be in place, and b) many are uncomfortable with keeping personal data like email on a third-party server. It's viewed as a privacy issue. They feel that Email sitting on a server they don’t control is wide open to access by law enforcement and other third parties.
As is always the case, I encourage you to research your email provider and check your email account server settings (or simply ask for help with this) on each of your devices and computers to see which method is being used and are you okay with it. Now knowing the difference between POP3 and IMAP, ask yourself these two simple questions - Which protocol do I prefer? and Which one is currently in place on my devices?