"Google is probably the best example: they see it as a trade secret: how many data centres they have, how big they are, how many servers they have."
One study by Brown, commissioned by the US environmental protection agency, suggested that US data centres used 61bn kilowatt hours of energy in 2006. That is enough to supply the whole of the UK for two months, and 1.5% of the entire electricity usage of the US.
With more than 1.5 billion people online around the world, scientists estimate that the energy footprint of the net is growing by more than 10% each year. This leaves many internet companies caught in a bind: energy costs are escalating because of their increasing popularity, while at the same time their advertising revenues come under pressure from the recession.
Demand for electricity is a primary concern, a secondary result of the explosion of internet use is that the computer industry's carbon debt is increasing drastically.