Arnt Gulbrandsen wrote:
IMAP certainly is more complex than POP, but I'm not sure that's
relevant to this issue.
If all you want to do is fetch a single message based on a URL, using
IMAP should be about as much work as POP. Things like IMAP's complex
support for server-side search don't matter to this simple task.
It depends on what protocols and implementation languages one is
familiar with. If one has been using something like C and is familiar
with other simple protocols (e.g. SMTP, NNTP, HTTP), POP is easy to
implement. Unless one is familiar with and actually likes programming
languages like LISP, one is unlikely to find implementing an IMAP
client to be pleasant, let alone easy. Aside from that, the simplicity
of POP's state-based protocol makes for a straightforward
implementation, as opposed to IMAP's asynchronous protocol (where
commands are tagged and response tags have to be matched to the
corresponding command).
The big issue though is that there doesn't appear to be a good mechanism
for responding to a mailing list archived message (or a message in a
list digest, in most cases) while preserving References etc. Lack of
support for IMAP and POP URI schemes may be a factor, but even widespread
support for those schemes would still require a means of getting the
message content into an application that can generate a response with
appropriate References, In-Reply-To, etc. fields. I suppose that could
in theory be done by having a browser launch a POP or IMAP email
application to retrieve the message, however in practice there would be
problems with that approach (e.g. launching Mozilla when there is already
an instance running doesn't work). And yes, the choice of POP or IMAP
doesn't really matter as far as addressing that big issue is concerned.