Do you access your email account from multiple computers? Have you added a smartphone to the mix as well? If so, you should be aware of IMAP. IMAP-enabled email accounts offer better email handling than old-fashioned POP email accounts.
Both POP and IMAP are communication methods used between email programs, like Apple’s Mail or Microsoft’s Outlook, and an email server. POP has been around for many, many years. It works just fine, but it’s model is outdated. IMAP was developed around the realization that people increasingly want to check their mail from multiple computers (or cell phones or other devices). Thus, some or all of your email is stored on the server, not on just one computer. Then you can set up a home computer, a work computer and a smartphone to all access (view) that email (using IMAP). You’ll see the same list of messages on each device plus you’ll see which messages are “new” or have the “replied to” mark next to them. If you delete a message from one device, it’ll be deleted from the server, then subsequently from each of the other devices when they next talk to the mail server. In other words your Inbox stays synchronized across multiple devices. This same type of synchronization can be set up for other mail folders like Drafts, Sent, and Trash, as well as saved messages.
IMAP is very useful. Personally, I think everybody should be using IMAP, even if you’re only using one computer currently. If you’re interested in using IMAP you could contact your email provider. Not all email providers offer IMAP service. Or if they do offer it, they sometimes charge more since IMAP requires increased storage space on the server and increases the server’s workload.
There is a common myth that if one uses IMAP that email messages ONLY reside on the mail server. This is not true. Each computer will store it’s own local copy of email messages on its hard drive. This way you can read or review email messages even if you don’t have internet access, such as while on a train or plane.
Here are 2 important consideration to keep in mind, if you decide you’d like to start to use IMAP. First, unfortunately, it’s not possible to simply toggle a setting to switch one’s email account from POP to IMAP. More specifically, what I’m trying to say is that if you have your email account setup in Apple’s Mail application and that account is configured to use POP then it can’t be changed to use IMAP. Instead, one has to add a new email account setup to Mail and specify that you’d like to use IMAP.
Secondly, you should ask your email provider how much storage space is allocated for your email account. When you’re using IMAP a copy of all messages in your Inbox, Sent and Trash folders lives on the mail server. If you let too much mail accumulate in these folders then you run the risk of having your email account fill-up.
This article in TidBITS gives some more detail about IMAP and its features. You don’t have to read the entire article, just a few paragraphs about how IMAP works.