Post Office Protocol Version 4 FAQ.

Why are there no questions in the FAQ?

Because nobody's asked me anything yet.

Why can't I download O3 yet?

The software is completed and tested (in fact, I'm running it now) but I have not yet finished the documentation or made any installation or build scripts.

Okay, now you can download it here

My first two questions are nearly the same:
What does POP4 have to offer that IMAP doesn't? Aren't you re-inventing the wheel?
and
How is it (pricipally) different from imap?

POP 3 is a nice simple protocol. It serves the purpose of enabling people to get their mail.
IMAP Is none of the above.
POP 4 adds some functionality to POP 3 while trying to maintain the simple ease of use design of POP 3.
IMAP isn't that either.
I realize that this would have been more appropriately done in 1998 when the idea was first presented to me, but the situation turned out that it was completed now. Maybe I could have made more of a difference, but at least from now on, I can try and spare future mail developers the grief of trying to implement an IMAP client or server by offering an alternative.

Although some of the features are the same, I'm not trying to create a Bradley armored vehicle, I'm trying to build a bicycle.