A big part of this problem is the way most people check their e-mail -- an old standard called Post Office Protocol, POP for short, that was developed for a far simpler time.

If we downloaded e-mail to only one computer, POP would still work. But between work and home computers and Web-mail options, it's easy to have three different routes to one inbox -- something POP was never designed for at all.

Trying to check a POP account from two computers is always a mess. If you download each e-mail to only one computer, you lose track of who sent you what.

But if you keep your messages on your Internet provider's computers until you've copied them to every machine you use, you can expect that mail server will eventually forget which messages you'd already retrieved, sending down fresh copies of every one and flooding your inbox with duplicates.

A better mail setup that solves those problems was developed over a decade ago and has been tested extensively since. But IMAP (pronounced "eye-map," it stands for "Internet Mail Access Protocol") suffers two flaws of its own: One is that most Internet providers don't offer it. The other is that most users don't know it exists. (full story)