Here’s a great Email post about how to write a proper Email client. Certain classes of software are just fundamentally difficult to do a complete job on, things you wouldn’t necessarily expect like a Textbox control or a build system. An Email client is one of these categories – even today if you discard legacy protocols and standards, you’ve still got a Mount Everest to climb. Here’s the epic mail, written by John C. Welch. Which is a shame, because at least on Windows and Mac, most of the desktop mail clients are sorely lacking in my opinion, with little hope of truly improving.

Some Quotes:

Stop thinking about IMAP as if it were some cohesive standard with a consistent implementation. It is not. It’s a bloody mess that manages to work in spite of its implementations, and Google’s IMAP implementation is one of the worst I’ve seen in the last 12 years I’ve been working with IMAP servers.

Regardless of who this project is aimed at, people using it are going to get email from “icky” sources, like Outlook users who have no control over their email format. (You think I’m kidding about this. I’m not. You should see how bizarre an overly locked-down windows shop can be.) They won’t have the option to get the sender to change format, so in addition to “normal” HTML, you should start thinking about building in TNEF decoding. In fact, if you do this well, it would be a monster point in the application’s favor, since that’s a major problem for people in the real world.

Power User != Programmer, Power User != Programmer, Power User !=
Programmer, Power User != Programmer, Power User != Programmer, Power User
!= Programmer, Power User != Programmer. There, point made.

HTML editor. Yes, I know text, blah, blah. Again, as the non-programmer power user, HTML is a reality, and it needs to be properly managed. There’s no reason to have the entire spec, but things like fonts, bold/italic/underline, alignment, real lists, and ‘real’ indents/tabs are not the work of satan. And that includes images. Welcome to the modern world, pretending it’s not there helps no one.