Subject: RE: IMAP v. POP (Was: The utilitiy of IP is at stake here)

From: Terry Gray <[email-masked]>
Date: Fri, 30 May 2003 17:34:09 -0700 (Pacific Standard Time)

Sorry for the sidebar distraction, those uninterested in POP vs. IMAP
should hit D now...

On Fri, 30 May 2003, Tony Hain wrote:

> Dave Crocker wrote:
> > The POP->IMAP example is excellent, since it really
> > demonstrates my point. IMAP is rather popular in some local
> > area network environments. However it's long history has
> > failed utterly to seriously displace POP on a global scale.
>
> Could that be because from the end user perspective IMAP doesn't provide
> any clear value over POP? Isn't IMAP all about shifting control of the
> mail store from the end user into the hands of the mail administrator?

Tony,
I strongly disagree with your characterization (and I believe Dave's
assessment is only true for residential ISPs, not enterprises.)

My own interest in and support of IMAP is totally driven by my
end-user needs.  IMAP lets me get at my INBOX from any of the multiple
machines I use every day.  IMAP lets me selectively fetch headers and
body parts to save time over slow links.  IMAP lets me access any of
my other incoming or archive folders from anywhere.  IMAP lets me set
status flags on my messages.  IMAP lets me know about new mail arrival
in real-time without hammering the server.

POP offers none of those benefits.  (True, you can fudge #1 via "leave
mail on server", but without any status flags, that's a dismal
option.)  IMAP is a functional superset of POP: it supports not only
"offline" (download-and-delete) access ala POP, but also "online" and
"disconnected" access modes (though I agree with the criticism that
"disconnected" capability, wherein local mail caches are automatically
synchronized with the server, is somewhat "under-represented" in most
IMAP clients.)

People who only use one computer (and who back it up regularly :), may
find relatively little benefit to IMAP --though I'd argue that
selective fetching is an increasingly big deal as low-quality wireless
Internet access becomes commonplace.  Moreover, I believe the trend is
toward more people using multiple devices to access their mail.

Currently it may be true that most residential ISP customers fall into
the single-computer-user category (for their personal mail), but I
suspect an equally important factor is that few of those same
customers have ever heard of IMAP or why they might find it useful. It
is also true that many service providers are concerned about disk use,
and indeed need to expect that IMAP users might keep more mail on
their disks.  Many small residential ISPs offer IMAP (for a sample,
see http://imap.org/products/providers.html) but I don't know of any
really large ones that do (although Milo assured me that @Home was
*going* to... :)

In contrast, I suspect that most enterprises use either Exchange/MAPI
or an IMAP-based solution (and of course Exchange also supports IMAP).
Hybrids are also possible, and those who need IMAP functionality but
wish to maintain control/responsibility for their mail store often run
their own IMAP server.

Therefore I claim that it is highly incorrect to suggest that IMAP
hasn't displaced POP "because from the end user perspective IMAP
doesn't provide any clear value over POP", or because it was "all
about shifting control of the mail store from the end user into the
hands of the mail administrator" --which I can assure you, it was not.

Cheers,

-teg

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From: Dave Crocker <[email-masked]>
Date: Wed, 4 Jun 2003 09:13:31 -0700

Terry,

TG> and I believe Dave's
TG> assessment is only true for residential ISPs, not enterprises.)

As I suspect Terry knows I know, the differences between pop and imap
are fundamental. I was making no comment on the utility of imap vs. pop.
This is about end-user adoption statistics.

i should have said 'enterprises' rather than LANs, since that was what i
was trying to highlight.  my understanding is that imap has had a large
impact on enterprise email access, though I've no idea what percentage
of the enterprise POP market it has displaced.

but 'residential ISP' is a rather large portion of the Internet and the
scale of the whole Internet is the focus of this discussion.

TG> People who only use one computer (and who back it up regularly :), may
TG> find relatively little benefit to IMAP

this is going to take us down a distracting path, but since you mention
it, i would have switched to IMAP long ago, for exactly the
multi-computer scenario you cite. but i have not come across an email
user agent with features I need that also has support for IMAP that
works acceptably.

TG> Therefore I claim that it is highly incorrect to suggest that IMAP
TG> hasn't displaced POP "because from the end user perspective IMAP
TG> doesn't provide any clear value over POP", or because it was "all
TG> about shifting control of the mail store from the end user into the
TG> hands of the mail administrator" --which I can assure you, it was not.

well, for many users, pop is just fine, of course.  they simply do not
need imap.

it is also true that residential ISPs tend not to see the business
benefit in storing user email.

but it is most clearly true that the two protocols provide massively
different capabilities and that each can be massively useful.

d/
--
 Dave Crocker <mailto:[email-masked]>
 Brandenburg InternetWorking <http://www.brandenburg.com>
 Sunnyvale, CA  USA <tel:+1.408.246.8253>, <fax:+1.866.358.5301>

---

From: "Anthony Atkielski" <[email-masked]>
Date: Wed, 4 Jun 2003 22:51:39 +0200

Terry writes:

> In contrast, I suspect that most enterprises use either
> Exchange/MAPI or an IMAP-based solution ...

Both solutions are extremely well suited to intracompany or
intraorganizational e-mail systems in relatively homogenous user
environments.  I'd always recommend Microsoft Exchange Server for such
applications over simple SMTP/POP3 solutions, if the bandwidth is not too
restricted.

However, for large, heterogenous, variable-bandwidth networks like the big,
wide Internet, SMTP/POP3 are far superior.  The more variables there are,
the simpler a system needs to be in order to have any chance of working
reliably for a large part of the user community.  SMTP/POP3 satisfy this
criterion; IMAP generally does not, and Exchange is an exercise in absurdity
in this context.