For Google’s rivals, one the hardest things to compete with over the years has been its relentless drive to bring continual improvements to the effectiveness of its search advertising.

Every quarter comes a stream of improvements designed to boost the monetisation of search results, increasing the click-through rate and ROI for advertisers – and Google’s own profits.

It is now on the same relentless path in a new market: display advertising. Today’s news that it has bought Teracent, a private company whose technology is used to customise and target display ads, is a warning to Yahoo that the pace of innovation is picking up. Read more