webOS Nation Forums - View Single Post

Chatter · 02:06 PM

It's been a while since this particular topic has appeared, so I thought I'd reprise some of what I've written before. Since Chatter has supported both for quite a while, this isn't at all an attempt to promote Chatter, but rather to answer questions that I seem to get every day in my email and that appear here frequently as well.

Advantages of IMAP

1. IMAP is far, far faster than POP3 and uses far less data; this is particularly true for large mailboxes. For example, just determining which messages need to be downloaded and/or deleted in a POP3 mailbox with 1000 messages would typically require 100k of data to be transferred; with IMAP, this would be closer to 8K. Also, loading, say the first 5 lines of an email would typically take 5x or more as much data as with IMAP. Doing a "load more" of a POP3 message requires 1) a full sync - the part that takes 100k for a 1000 message mailbox, plus 2) reloading everything in the message from prior to the "load more". With IMAP, only the "more" part gets loaded; this is a HUGE savings.

2. IMAP is far, far more efficient at dealing with attachments. To even determine whether attachments exist, the entire message must be loaded (a horrible example would be the case of a 1k attachment following a 1MB attachment; in POP3, you wouldn't even know the 1k attachment existed until reading the entire 1MB attachment). In IMAP, attachments are known completely at the outset and each can be loaded independently.

3. IMAP keeps state information on messages - replied, seen, flagged; none of this is possible on POP3. Read a message on your Treo and it appears read in Outlook back at home, or in the office.

4. IMAP allows unlimited nested folders that appear on every client; in POP3, folders are local - messages "filed" in this way on one device can't be seen on any other device.

5. IMAP allows true push operation; POP3 does not. (Most IMAP servers support this, including AOL/AIM)

6. IMAP allows mailboxes to be completely sync'ed, so that changes made on one device are reflected on the other; no more worries about "where" a message lives (this is akin to webmail). With POP3, it's hard to know whether a message read on one device will even be available to another device (especially with Gmail!).

7. IMAP allows sent mail to be uploaded back to the server, so you can keep your sent mail in one place; POP has no such facility.

8. IMAP is relatively inexpensive, $20/yr or less in many cases. (I happen to offer an account like this with 6 months free to start). Some are "free", like AIM.

9. Most POP3 accounts allow forwarding to IMAP (GMail and Yahoo come to mind); used this way, you get all the advantages of IMAP while keeping those old addresses. Many (everyone.net, fastmail.fm, and fusemail.com) even allow you to use your POP3 return address, so that replies appear to come from the original address!

10. IMAP is supported by all major PC/Mac clients - Outlook, Outlook Express, Thunderbird, Mac Mail, Entourage, Pine, etc...

I'm sure there's more, but this is a good start...

03/03/2006, 01:53 PM	#1 (permalink)
Chatter Member Join Date: Sep 2002 Location: Oregon Posts: 4,226 Likes Received: 0 Thanks: 0 Thanked 0 Times in 0 Posts	Why IMAP vs POP3... It's been a while since this particular topic has appeared, so I thought I'd reprise some of what I've written before. Since Chatter has supported both for quite a while, this isn't at all an attempt to promote Chatter, but rather to answer questions that I seem to get every day in my email and that appear here frequently as well. Advantages of IMAP 1. IMAP is far, far faster than POP3 and uses far less data; this is particularly true for large mailboxes. For example, just determining which messages need to be downloaded and/or deleted in a POP3 mailbox with 1000 messages would typically require 100k of data to be transferred; with IMAP, this would be closer to 8K. Also, loading, say the first 5 lines of an email would typically take 5x or more as much data as with IMAP. Doing a "load more" of a POP3 message requires 1) a full sync - the part that takes 100k for a 1000 message mailbox, plus 2) reloading everything in the message from prior to the "load more". With IMAP, only the "more" part gets loaded; this is a HUGE savings. 2. IMAP is far, far more efficient at dealing with attachments. To even determine whether attachments exist, the entire message must be loaded (a horrible example would be the case of a 1k attachment following a 1MB attachment; in POP3, you wouldn't even know the 1k attachment existed until reading the entire 1MB attachment). In IMAP, attachments are known completely at the outset and each can be loaded independently. 3. IMAP keeps state information on messages - replied, seen, flagged; none of this is possible on POP3. Read a message on your Treo and it appears read in Outlook back at home, or in the office. 4. IMAP allows unlimited nested folders that appear on every client; in POP3, folders are local - messages "filed" in this way on one device can't be seen on any other device. 5. IMAP allows true push operation; POP3 does not. (Most IMAP servers support this, including AOL/AIM) 6. IMAP allows mailboxes to be completely sync'ed, so that changes made on one device are reflected on the other; no more worries about "where" a message lives (this is akin to webmail). With POP3, it's hard to know whether a message read on one device will even be available to another device (especially with Gmail!). 7. IMAP allows sent mail to be uploaded back to the server, so you can keep your sent mail in one place; POP has no such facility. 8. IMAP is relatively inexpensive, $20/yr or less in many cases. (I happen to offer an account like this with 6 months free to start). Some are "free", like AIM. 9. Most POP3 accounts allow forwarding to IMAP (GMail and Yahoo come to mind); used this way, you get all the advantages of IMAP while keeping those old addresses. Many (everyone.net, fastmail.fm, and fusemail.com) even allow you to use your POP3 return address, so that replies appear to come from the original address! 10. IMAP is supported by all major PC/Mac clients - Outlook, Outlook Express, Thunderbird, Mac Mail, Entourage, Pine, etc... I'm sure there's more, but this is a good start... Last edited by Chatter; 03/03/2006 at 02:06 PM.