Today, Facebook purchased Instagram – maker of the wildly popular iPhone and Android photo-sharing app of the same name – for $1 billion. That’s a lot of money for a company that’s less than two years old and has no real revenues. But viewed historically the deal is a smart one. Facebook founder Mark Zuckerberg is onto something. The human desire for self-expression – to say something as simple as “I’m here” – is insatiable, and Instagram exploits it superbly.

Sometimes the simpler the message, the more urgent the need to share it. Example: The first thing most people do upon landing at an airport and being told by the captain they can now use their mobile phones is to whip it out and tell someone – anyone! – where they are and where they’re going.

In buying Instagram, Zuckerberg acknowledges that his company’s own mobile app is an inconvenient, ineffective way to say “I’m here.” Using Instagram to transmit pictures of San Francisco, shots of the ballpark or plates full of food to other smartphones lets users convey their here-ness in greater detail and precision than the overcooked stew that the Facebook platform allows. And there is no learning curve: All you need to make an Instagrammatic statement is 1) a mobile device with a camera, 2) an itchy trigger finger and 3) an Instagram account.

Instagram marks the latest point on a communications timeline that starts with the telephone’s invention in the mid-1800s. As Paul Starr writes in The Creation of the Media (2004), “the telephone originated in an effort to improve and extend the telegraph, not to replace it.” None of the early telephone visionaries of the day imagined that nearly every household would subscribe to telephone service and place calls to other subscribers for personal chats. It was a commercial device, too expensive to be wasted on self-expression. Only as costs fell did the telephone stop being a business luxury and become a shared family essential over which everything from grocery orders to courtship was transmitted.

Telephone reigned as the supreme communications device until the early 1990s, when pagers (those now mostly forgotten texting machines), fax machines and email began to undermine it. Email might have supplanted the telephone even faster if the first big online companies – CompuServe, Delphi, Prodigy and the rest – had given email greater primacy. That innovation came from the upstarts at America Online, who understood that what people wanted most from the online experience was not a new version of the SkyMall or back issues of PC Magazine or an online weather report, but a simple user interface that facilitated self-expression in chat rooms and email. AOL’s email victory was temporary, however, as the universal Internet became ubiquitous. Email over the Internet worked so well that telephones around the world stopped ringing!