The bathtub was invented in 1842. The telephone was invented in 1876. That means you could have sat in the bathtub for 34 years without the phone ringing.
The telephone was perhaps the first kind of real-time communication the world has ever known. And the ringing of the telephone is the insistent reminder that someone else's choice of a time to talk is being imposed upon you, on the receiving end: "hey, I want to talk to you, RIGHT NOW!". And, by convention, you have about 15 seconds to make up your mind about whether or not to answer the phone. That phenomenon has caused a lot of anxiety of the past hundred years, I'm quite sure of it.
Given that it took roughly 100 years for regular people to have answering machines and they weren't even invented until 1942, there was no respite from ringing phones for a very long time. My mother still can't resist the sound of a ringing telephone, answering machine or not [why is it that technical people always use their mothers as examples?]
There is a deep issue rooted in all of this: availability. Up until roughly the 1970's, if the phone rang, you had to answer it, or you would never know what you might have missed out on. The answering machine was a revolution, and to this day you can't watch a movie, futuristic or not, without somebody screening calls on an answering machine (ever notice how no on-screen actors ever seem to have voice mail? it's because you can't screen calls, an important plot twist in almost all movies).
Caller ID was another, smaller revolution in the telephone availability game: now you can consider whether or not to answer a call based on who it is that's calling.
These are not small things. They fundamentally shifted the balance of power from the caller back to the person being called. It saved the telephone from the scrap-heap of history, in my opinion, because without operators and administrative assistants (which few people carry on their belts along with their cell phones) it just isn't good use of time to answer the phone unless you know who's calling you.
This broadens into a much more interesting issue when you take it into the realm of other real-time communications vehicles -- like instant messaging. The only difference between email and instant messaging (for the most part) is that IM is considered to be real-time. Yet part of the power of email is that people can respond to email up to three days after it is sent and still considered socially acceptable.
So which is better? And why? The title of this blog, and the underlying rhetorical question, is who's time is it? mine, or yours?
People guard their time more jealously than perhaps anything else, as we've been taught that Time is Money, and we never have enough of it. So technologies that boast "real-time" components absolutely must consider whose time it is, and how they'd like to manage it. This goes for instant messaging, collaboration, meeting scheduling, the whole gamut.
A phrase that hasn't gotten much press but is absolutely critical for efficiency in our global 24/7 economy is time shifting. This is the idea that you can move things around in time but still keep them conceptually the same. Email is the best example: it is the same as instant messaging, except the sending and responding can be time-shifted. They're not in real time. They can be, if both parties are sitting at their desks and hitting the Send button; email uses the same transport as IM and, give or take the polling of POP and IMAP servers, just as fast. But the point is that choice of timing is up to the participants. Which is as it should be.
In my view, the technologies that succeed in the long run will be those that enable information workers to manage their time as they choose, on their terms -- time shifting. This is in direct opposition to the notion of "real-time", which, to me, is a lot like the phone ringing while you're in the bathtub: it's real-time when you're calling, and it's a compelling nuisance when you're the one being called.