Websites and apps are frequently described by their creators as offering a 'rich experience'. The beautiful designs, intuitive layouts and compelling interactivity may well be engaging and satisfying to use, but when they're hailed as being a 'feast for the senses', it's evident that they're a feast for merely two.
Online entertainment is about sight and sound; everything is mediated through a glass panel and a speaker, leaving us well short of being immersed in an alternative reality.
But with studies having demonstrated that more than half of human communication is non-verbal, scientists have been working on ways of communicating touch, taste and smell via the internet.
"What do you smell?" asks Adrian Cheok, professor of pervasive computing at City University London. The whiff of melon is unmistakable; it emerged from a tiny device clipped to an iPhone and was triggered by Cheok standing on the other side of the room.
In the shorter term, the applications of these devices seem slightly frivolous. "Fortunately, or unfortunately," he says, "that's where they've decided that the money is.
"But we need to explore the boundaries of how these things can be used, because scientists and inventors can't think of all the possibilities."
Our transition to an internet of all the senses is evidently dependent on the breadth of information that can be conveyed from one person to another as a series of zeroes and ones. "You have to find a way of, say, transmitting smell digitally, without using a sachet," says Cheok. Few of us can conceive of the pace with which technological power is developing. Ray Kurzweil (author, futurist, and a director of engineering at Google) predicts that, by 2025, we'll have a computer which has the processing power of the human brain. Cheok sees this as a hugely important tipping-point for society.
Society will also have to work out how it's going to handle the hyper-connectivity of a multisensory internet – bearing in mind that we can already become deeply frustrated by the few kilobytes of information contained within the average overloaded email inbox.
"Our brains haven't changed to cope with infinite communication," says Cheok. "We don't have a mechanism for knowing when there's too much, in the way that we do when we've eaten too much.
"Communication is not just a desire, it's a basic need – but we've gone from being hunter-gatherers in groups of 20, or 30, to being in a world of infinite data. We could literally gorge on communication and be unable to stop."
Marshall McLuhan, the Canadian philosopher of communication theory, famously used the term "global village" to describe the effect of connected media upon the world's population.
Cheok believes that new sensory-communication channels will demonstrate how prescient that prediction was.
"For most of human history, we didn't have privacy," he says. "Everyone knew who was doing what. And these developments will mean that we become more and more open; almost bringing us back to the way that life used to be in hunter-gatherer times. Except, of course, it's now global."
The implications of the work of Cheok and his contemporaries seem to sit midway between exciting and terrifying, but in the shorter term it's about focusing on relatively mundane objectives, such as emitting multiple odours from a smartphone.
"People will get used to this new mode of communication," says Cheok, "and develop new languages.
"We don't yet have a language of smell, or touch. But, combined with emotion and the subconscious, it'll bring a heightened sense of presence.
"I've no idea what that will feel like, but I've always believed that human communication goes far beyond the logical."