Toymaker Hasbro bills it as "the biggest game of Monopoly of all time." Monopoly City Streets uses Google maps data, allowing users to buy any street in the world and add it to their real estate empire. Once you own a street, you can charge other players rent and build new property.

The website www.monopolycitystreets.com is currently responding slowly due to the rush of people eager to buy their own street. But the experiment will run until the end of January 2010.

This is the first time Google data has been used in a worldwide game and we expect similar ventures to follow from other online partnerships.

Whole new streams of advertising could be generated for Google in the virtual world. Perhaps virtual billboard advertising could outstrip the real world at some point in the future.

On the downside we may see private citizens battling for control of their virtual streets preventing companies from erecting virtual eyesores outside their virtual houses. Or PPC adverts fly-posted on our virtual national monuments.