Remember the days when email first appeared? It was asynchronous, 1:1 communication — a way of leaving a message without needing to interact in real-time with the person in question. Other communication protocols had tried this before (telegraph, fax, regular post), but nothing was faster. Email could also carry files and support better interactions — again, asynchronously.

When email first appeared, it seemed a gift to the busy professional, parent, or student. You could time-shift and time-manage in entirely new ways.

But was asynchrony really a feature? Or was it a bug, an unavoidable side-effect of a low-bandwidth world?

Nicholas Carr has an interesting post on this topic, one that recognizes that the real-time Web is bound to increase in importance as initiatives like Google Wave and the already familiar Twitter and Facebook offerings become more immersive. Even online video is becoming synchronous, as U2 will be broadcasting a concert live on YouTube later this month. Bandwidth is becoming something with a new upper limit to test.

Of course, Carr doesn’t see this new level of immersion as all that attractive:

The transaction costs of interpersonal communication have fallen below zero: It costs more to leave the stream than to stay in it. The approaching Wave promises us the best of both worlds: the realtime immediacy of the phone call with the easy broadcasting capacity of email. Which is also, as we’ll no doubt come to discover, the worst of both worlds. Welcome to the conference call that never ends. Welcome to Wave hell.

Email has other niceties. You can respond when you want to, add people to a response or cut some out, blind-copy or cc people as you see fit, etc. As Carr puts it,

Email delivered us from the telephone’s realtime stream. Suddenly, we controlled, individually, our main communications medium, rather than vice versa. We could choose when to read our email, and, more important, we could choose when to respond – and whom to respond to. The buffer was built into the technology.

This concept of buffers built into the technology is vital to thriving in the emerging online world. Even the telephone now has the buffers of caller ID and voicemail and call-waiting to manage the information triage and flow. But do our digital offerings?

The interfaces of today don’t support the synchronous world of tomorrow. As Google Wave demonstrates, our interfaces are changing, but are they changing in a way that keeps users in control?

Interface designers should start paying attention to the real-time web and assuming a world of synchrony rather than presuming an archival web and a world of asynchrony. Publishers and information providers should begin to plan for a world of complete data immersion and realtime access.

But these plans should leave the user in control. Just the other day, Amazon introduced a way to have your order status updated by SMS/text messaging. And why did I hesitate to invoke it (even though I’m a huge fan of checking my order status)? Because I wasn’t sure how many text messages I was setting myself up to receive. One every time a scanner kissed a label? One per day? And once the texting started, it’s very difficult to stop.

Customers are living in a world immersed in bandwidth. The metaphor of the page is gone and soon to follow is the concept of bounded information. But to keep our sanity and our customers, we need to learn how to implement and design user controls, buffers, and sanity into this new world of synchrony and bandwidth.