Normally, in fact, The Future of Something. Or, more specifically, The Future of Something Related To Our Client's Business. Personally, I've done The Future of Cars, The Future of Running (twice), The Future of Money and The Future of Media. And I'm old enough, and have lived long enough, to see none of my predictions come true.
The future, it turns out, is an unpredictable business. But, to offer you the benefit of all that failure, here is what little I've learnt. First, technologies and media techniques can change almost overnight. I know it's obvious but we forget it all the time. To quote a Tweet from Clay Shirky: "Why I ignore all 'five-year plans': five years ago, YouTube and Twitter didn't exist, and Facebook was only for college kids."
This will seriously affect you if you deal with technologies and media techniques. These things may appear fixed and certain, but they very rarely are. Printing or broadcasting, or what-have-you, are magnificent, effective technologies, but people will always try to improve them. On top of this, they will always find novel and exciting new things to do with them.
The second (and only other) thing I've learned about Futures I've gleaned from two magnificent new novels. Generation A by Douglas Coupland and Makers by Cory Doctorow. It's pretty simple - the world will change, but we probably won't. These two books are set very slightly in the future, in worlds knocked aside by technological and social change. They are both worth reading for their imaginings of technological and media possibilities, but they're more interesting because of what they tell us about human nature.
If I had to guess, I'd suggest that both Coupland and Doctorow had read Stumbling Upon Happiness by Daniel Gilbert, because their characters are embodiments of Gilbert's idea that our levels of happiness and satisfaction remain broadly the same whatever happens to us. He points out that we're tremendously bad at predicting the emotional effects of good or bad news. We assume that grief will completely devastate us or a brilliant new job will change everything for the better. This, typically, isn't true.
We return to previous levels of happiness, we remain the people we were before. That's true of Coupland's and Doctorow's characters and scenarios and it's why their futures are plausible. Economic collapse doesn't stop us wanting nice things, recovery won't turn us into avaricious monsters. That's what most of us get wrong when writing about the future, we think change in the world will change us. It probably won't.