With the rise of rapid-fire messaging, the digital letter seems to be crawling toward the fate of snail mail. If your in-box

With the rise of rapid-fire messaging, the digital letter seems to be crawling toward the fate of snail mail.
   If your in-box is currently reporting unread messages in the hundreds or thousands, you might have a hard time believing the news: e-mail is on the decline.
   The total volume of e-mail has dropped about 10 percent since 2010. The word "e-mail" itself tells you about its origins: it was modeled on written letters. To this day, a lot of e-mail begins with a salutation. Maybe it’s "Hey" instead of "Dear Casey", but it’s there. And because there was so much overhead involved with sending a letter — folding, enveloping, addressing, stamping, mailing — few bothered to send only a few pithy words. The effort seemed to justify a longer message. Once heralded as the death of the personal human touch, e-mail has now taken over the letter’s place as a ubiquitous form of communication — both business and personal. But is its day in the digital sun coming to a close?
   At first blush, that might seem to be the case. The incoming generation, after all, doesn’t do e-mail. Oh, they might have an account. They use it only as we would a fax machine: as a means to communicate with old-school folks like their parents or to fulfill the sign-up requirements of Web sites. They rarely check it, though. As of just a few years ago, among 25- to 35-year-olds, e-mail had already dropped 18 percent — and among teenagers, it was down about 60 percent. A Microsoft human resources guy recently told me that lately, applications from recent college graduates leave the "e-mail address" field blank. It’s considered too unwieldy, uncool, not immediate enough.
   Today’s instant electronic memos — such as texting and Facebook and Twitter messages — are more direct, more concentrated, more efficient. They dispense with the salutation and the signoff; we already know the "to" and "from". Many corporations are moving to messaging networks for exactly that reason: more signal, less noise. And less time.
   This trend is further evidence that store-and-forward systems such as e-mail and voicemail are outdated. Instead of my leaving you a lengthy message that you pick up later, I can now send you an unobtrusive, easily consumed message that you can read — and respond to — on the go. The decline of e-mail corresponds neatly to the dawn of the mobile era. Let’s face it: e-mail has historically been an activity. You sit down to do it. You fill up a block of time. And long missives are clumsy on a phone.
   But instantaneous written messages are different. These are neatly tailored to fit in just about any time: before a movie, in a taxi, waiting for lunch. And because these notes are invariably brief, they’re a natural for smartphone typing. With these formats, you also have control over who can correspond with you, which you usually don’t in e-mail. And especially on Facebook, instant messaging can take on the character of a chat room, where several people can carry on at once.