Not all the results that appear high up on Google's results pages are there because a dispassionate algorithm has filtered them out from a mass of less relevant material on the web.

Google's own specialist services, such as its maps and weather reports, are often given pride of place over similar services from other companies. That has brought complaints this year that as it extends its reach into new corners of the online world, Google can use its dominance in search to give its own services an unfair advantage.

Google engineer Amit Singhal dismisses that claim as “very unfair”. The company's only aim in drawing information from its own services, he says, is to give its users quicker answers to their questions: “It's all about user value and information. Our job is to answer the query the user wants with the best piece of information,” he says.