Google’s announcement that it will offer ‘interest-based’ advertising to key partners on YouTube and its AdSense publisher network from next month, with a wider rollout later this year, raises the ante for behavioural targeting

Targeting based on users’ activity on publisher websites has become widespread, but concerns over privacy have slowed deployment of technologies that track users’ entire click-stream activity on the internet, such as Phorm

Exponents believe that behavioural targeting will boost the market for internet display, which we estimate was worth £650 million in 2008. In our view, its main impact will be to accelerate the shift to performance-based pricing