Ignore the hype over big tech. Its products are mostly useless | John Harris

It's years since Silicon Valley gave us a game-changer. Instead, from curing disease to colonies on Mars, we're fed overblown promises

Back in 1999, Google hit 1bn searches a year. Wifi began to make an impact about two years later. Thanks to the pioneers of Facebook and Twitter, the age of mass social media dawned between 2004 and 2006 - and non-stop posting, messaging and following was soon enabled by the iPhone, launched in 2007. These things have changed the world and, in hindsight, the way they became ubiquitous had a powerful sense of inevitability. But the revolution they represented is old now, and nothing comparable has come along for more than a decade.

Despite this, a regular ritual of hype and hysteria is now built into the news cycle. Every now and again, at some huge auditorium, a senior staff member at one of the big firms based in northern California - ordinarily a man - will take the stage dressed in box-fresh casualwear, and inform the gathered multitudes of some hitherto unimagined leap forward, supposedly destined to transform millions of lives. (There will be whoops and gasps in response, and a splurge of media coverage - before, in the wider world, a palpable feeling of anticlimax sets in.)