I have no idea how fruit machines work. Sure, I get the 'line up three bunches of cherries to win' classic, but the all-singing-all-blinking monstrosity that mocked me in the pub yesterday? Absolutely clueless. And yet, somehow, its combination of twinkly lights, bashy buttons and blippy noises had me chucking coins into it like owning money was going out of fashion.

That's because, as a species, we're far more likely to engage with something if there's an element of gaming involved. I'm sure there's an evolutionary imperative behind all this: if you took a chance on the lady monkey with the weirdy, opposable thumbs, there was a better chance your offspring would survive the great banana famine of 7,000,000 years BC. That kind of thing. Don't ask me, ask Richard Dawkins.

Anyway, we love gaming (and its sidekick, competition), and the introduction of these elements - conceptually known as 'gamification' - into any environment works wonders. The LinkedIn profile completeness bar is a famous example, and rightly so: users fill in more and more info to achieve a 100% complete 'score' and, in so doing, provide mountains more data back to LI, its users and, of course, its