There are 2 ways your email can be set up: POP and IMAP. Do you know the difference between POP and IMAP? Read on!
POP stands for Post Office Protocol. It is a standard way for computers to send and retrieve email. Most mail hosts, including Yahoo and Gmail, support POP.
If your mail is set up as POP, that means your computer connects to your mail host (Yahoo or Gmail or GoDaddy or 1and1 or whatever company is hosting your mail), pulls in all the new mail since the last connection, and then deletes the mail on the mail host before disconnecting. This means that your computer is the only location where all incoming and outgoing mails are stored.
The problem is: What if you have 2 computers, one at the office and one at home? If you connect to your POP mail and download new mail while in the office, then those messages won’t be readable on your home computer when you go home at night, because they only get stored in one place. (Although there are exceptions to this.) Same story with your smart phone.
IMAP stands for Internet Message Access Protocol. If your mail is set up as IMAP this means that your mail host (Gmail or any other company hosting your mail) has a master database of your mail, and all the folders you’ve created to store the mail. You can log on to access the mail from multiple computers and smartphones, and the mail and folders will look the same everywhere. If you read a message on your iPhone, it will show up as read on your computer. If you send a reply from your work computer, it will also appear in your sent mailbox on your home computer. And so forth.
Many email hosts did not offer IMAP mail until recently, so many people are using POP mail even though IMAP has many advantages.
The one disadvantage to IMAP mail is that it requires a lot of storage space at your email host company, as all your mails will be stored there on an ongoing basis. So if your email host charges a lot of money for storage space, you may want to either stay on POP or move to a different mail host.
Both Mac and PC computers can support either POP or IMAP mail.
On a Mac, the 3 most common pieces of software for reading and sending email are Apple Mail (the postage stamp), Entourage, and Outlook: all 3 of these can be set up for either POP or IMAP mail.