Here we go again. Barely more than a decade since the last internet bubble deflated, valuations for digital businesses are again rocketing skyward, a frothiness eerily similar to the last round of irrational exuberance. Once more, Silicon Valley shows every sign of considering itself to be the centre of the universe.

Venture funds, parched from a decade of drought, are again besieged by eager investors and are, in turn, just as eagerly vying to fling their capital at youthful entrepreneurs. Megabillionaires – at least on paper – are being minted at dizzying speed, often seemingly overnight. The sizzle and new wealth has pushed Valley real estate to startling heights; one “home” recently sold for $100m to a Russian venture capitalist who had amassed a Facebook fortune.

Perhaps the most tangible manifestation of the euphoria came late last week, with the initial public offering of LinkedIn. Launched in 2003, just after Mark Zuckerberg entered Harvard, the company had muddled along as a sweaty professional networking site for the would-be upwardly mobile and a talent pool into which prospective employers could dip.