Numbers like $800 million, or even $2 billion, tend to focus the attention rather sharply. Which is why - in a bid to better understand in-game advertising - Sony US is planning to allow TV-ratings company Nielsen to track the games its customers play.

The GamePlay Metrics scheme will see Sony supply Nielsen with data about which games people are playing on the PS3 and PlayStation Network for how long and how often. It will track the games rather than individual players. Nielsen will combine the data with its own information from over 12,000 US households already in its TV-habit-monitoring orbit.

Changing the game

Product placement in games is nothing new. But many companies are unwilling to commit to advertising in a medium whose 'stickiness' has been poorly understood until now. Once non-specialist firms get hard data about how often their advertising could be seen in games, that may change.

Oh, and $800 million is what an analyst quoted in the LA Times reckons the in-game ad market will be worth in 2012. And the $2 billion figure could be the amount advertisers spend in all game-related settings by the same year. While it's peanuts compared to mainstream advertising, the growth potential is obvious.