All technology extends some pre-existing human urge or condition: a hammer extends the hand, a pencil extends the mind, a piano extends the voice. All technology amplifies something we already possess.
Technologies become viral when they amplify something that is already in us, but blocked. When a technology eliminates a major blockage, the uptake can be explosive. Facebook gained 500 million users in under 5 years by finding a basic human blockage (our need to share and connect), and offering a way around it — as a surgeon might extract a clot to restore the flow of blood.
When designing technology, you should understand what human urge or condition you will be extending.
There are many kinds of urges. There are the seven deadly sins (lust, greed, envy, sloth, gluttony, pride, and wrath). There is the urge to find meaning, joy, wonder, and happiness. There is the urge to explore, to improve, to learn, to gain wisdom, to teach. There is the urge to feel loved, to connect, to feel useful, to nurture, to help, to belong.
Each urge, when extended, creates a different kind of outcome and a different kind of person.
When millions of people have a given urge extended, it creates a different kind of world.
So choose your urges wisely.