The virtual assistant Penn Today

The doggie raincoat was cute the first time around, modeled by an adorable mutt and found through an intentionally clicked link. But then, like an Internet phantom, the canine outerwear kept showing up, in ads along the right-hand side of an email browser, in Facebook, and in several news articles. A product seen on a website visited once reappeared as if multiplying. It's an experience that just about anyone who does anything on the web these days has likely had: Click on a link or visit a website and suddenly, that item follows your electronic path. The strategy is called ad remarketing, and it's intended to capture the 98% of would-be consumers who view a product but don't buy it.