About a dozen years ago, we began to talk about the age of conversation as the web evolved to enable us to spend more time on platforms that connected people together rather than the one-way questioning of information that characterised the nature of the early web. It was a dramatic shift in our relationship with the web and had a significant impact on marketing but this shift is likely to feel far smaller than the real age of conversation we are entering now - the era of the conversational interface.

The conversational interface puts dialogue at the centre of the interaction between technology and people. Its rise, technology difficulty apart, is unsurprising: human beings are inherently social in nature (as Mark Earls rightly reminds us) and conversation is the behaviour that enables social human interaction. It's not a surprise that, of the top ten apps, all are social in nature and six are primarily used for messaging. And despite all the apps and services available to us, more than half the time we spend on our phones is spent talking, texting or emailing.

The rise of the conversational interface has mistakenly been called the rise of zero interface when in fact it's the next natural evolution of the interface as we continue to remove the layers of translation required between machines and people (think of how inputs have evolved over the past 60 years or so from punch cards to keyboards to touch to voice, and from the language of code to natural language). Conversations can now exist directly between humans and services.

Now, this is obviously very clever technology. But what's really interesting for marketers is that this is a new type of platform for which to design experiences. We're already beginning to see the first branded efforts. The most talked about of these has been the new mobile app for the news site, Quartz. Its onboarding feels chummy and it quickly begins to learn what type of information you like. It feels at first like a remarkably fresh way to receive news but I can't help but feel that this is an interface that is far more about novelty than substance. After a few days I was getting tired of what felt like a rather overbearing tone of voice with the need for far too frequent interaction, and my usage dropped accordingly. The novelty simply wore off. So what should we be thinking about if we're to build conversational interfaces that are magnetic, have longevity, and are better than what's come before?

The most obvious thing to think about is giving the interface a distinctive tone of voice: it should feel like you're having a very different conversation with Nike than with the government, for example. Rather than the increasing standardisation we are seeing in interfaces today due to the misuse of, and blind allegiance to, so-called best practices, conversational interfaces give brands the chance again to make their interactions feel different. The art of writing, often downplayed on the web, will be an old weapon that becomes new again to build more magical experiences.

As a result, we will have to think about changing brand guidelines to be less about the static personality of brands and more about how they converse and build relationships. Tempo of conversation becomes important. We will need to build friction and delay into experiences we are currently measuring by speed to make them feel more natural and less robotic. We will have to think about how often and when we interact with people and how and when we evolve the nature of the relationship. We should ask for feedback so we can get better and more useful. Over time, we will need to be able to learn behaviour so we can be a little bit more automagical and answer questions before we are asked them.

But most of all, returning to a theme from a past issue, the best conversational interfaces will be designed to be human-friendly rather than human-like. We are likely to see lots of new interfaces that try too hard to feel like a human. They’ll have friendly names and an overbearingly chummy or patronising tone of voice. They’ll want to talk to us too often and at the most inopportune times about subjects in which they have no expertise. The ones that will win, I believe, will be the ones that show the most restraint and don't try to talk with us 24/7. Just because you can have a conversation doesn't mean you always want one.