Ghost of a new bubble: why the unprofitable companies began to cost billions

The technological companies so-called new economy many years in a row do not make profit and burn money, but nevertheless are estimated at billion dollars. Why so occurs, how many will last and to what will lead? Market analysts of ten years used standard indicators for an assessment of companies: revenue, EBITDA, price to equity, etc. For the profitable paid more, for unprofitable it is less. And suddenly the world went crazy...