Retargeting Ads Follow Surfers to Other Sites

People have grown accustomed to being tracked online and shown ads for categories of products they have shown interest in, be it tennis or bank loans. Increasingly, however, the ads tailored to them are for specific products that they have perused online. While the technique, which the ad industry calls personalized retargeting or remarketing, is not new, it is becoming more pervasive as companies like Google and Microsoft have entered the field. And retargeting has reached a level of precision that is leaving consumers with the palpable feeling that they are being watched as they roam the virtual aisles of online stores.