The Killer App! It's practically legendary. It's the great American novel. It's the fountain of youth. It's the great white whale, the Holy Grail and the pot of gold at the end of the rainbow. It's ... e-mail!
That's right. E-mail is the killer app. It's what everyone who uses the internet has in common. Doesn't matter if you're a researcher or a programmer or a secretary or a store clerk or a kid looking for porn. Everyone uses e-mail.
And e-mail sucks!
Historically, e-mail goes back to the late 1960's or early 1970's, when all computer users were geeks. E-mail was just a way of moving files from one user to another on the same computer. Then the ARPAnet came along in the 1970's, and the idea was extended to sending plain text from a user on one computer to a user on another. Since then, it's gotten loaded down with every imaginable kind of baggage ... HTML, file attachments, links to Web pages, etc.
I'm all in favor of having nicely formatted e-mail messages, with embedded images, links, etc. But the way these things were added was pretty haphazard. Most of this stems from a specification called MIME (Multipurpose Internet Mail Extensions), basically allowing a mail message to be conglomeration of different components, in different formats, allow loosely held together. Unfortunately, although MIME allows all these parts to be assembled, it doesn't allow, for example, new text in a message to be distinguished from quotations from earlier messages, except by guesswork. The MIME format is very primitive compared with something like XML, but because there are so many e-mail archives and so many programs that support it, we're stuck with it.
I think most people would agree, however, that e-mail's biggest weakness is its lack of security. Anyone can forge an e-mail message, and spammers routinely do this. There's no way to detect who actually sent a message, or whether its contents have been tampered with.
We have technologies to solve all this, but it would take a major effort to replace the current e-mail structure. We need to really launch an initiative to introduce a completely new e-mail infrastructure, in parallel with the existing one until the new structure is fully deployed, and the old one can be scrapped.
Until then, we'll be stuck getting bombarded with a dozen spam messages for every legitimate one we receive. It really is the killer app.