Version:            (using KDE 4.1.1)
Installed from:    FreeBSD Ports

When using IMAP, KMail should offer the option of prefetching the next email (or emails?) that the user is likely to read so that when they go to the next message, it is likely to already be available on the local computer.  This would make KMail *much* more responsive, especially for users with slow connections to their mailservers.

I would suggest making this setting a slider for the number of emails to prefetch, from 0 (the default and current behavior) to, say, 5 or 10 (which seems high, but hey, some people might like that).

Limit prefetching to the current folder; lots of people have mailing lists or other mail that they don't read often unless they specifically visit those folders.

Do not change the status of a prefetched message in any way.  In particular, don't mark it read just because it's been retrieved.

Suggestions for the which message to fetch:

- The next unread message
- The message listed immediately above the current message
- If the user most recently used "Previous Message" or "Previous Unread Message", then then the same as above but in the other direction

I don't think I'd make the ordering configurable since I think the above would work for almost everyone.

Again, I think this could make KMail feel much more responsive for a lot of people with little additional overhead.  Since I'm very likely to read the email after the one I'm currently looking at, KMail should get it for me before I ask for it.