My old boss Marc Andreessen liked to say that every failed idea from the Dotcom bubble would work now. It just took time - it took years to build out broadband, consumers had to buy PCs, retailers and big companies needed to build e-commerce infrastructure, a whole online ad business had to evolve and grow, and more fundamentally, consumers and businesses had to change their behaviour. The future can take a while - it took more than 20 years for 20% of US retail to move online. People forget thi...