“Tucker has focused her studies on the growing number of personalized ads. In an experiment with an online travel firm, for example, she saw that ads tailored to a specific browsing history were, on average, less effective than generic ads for the site when shown to people who had recently visited. “You’ve been to the website and looked at the products. There’s probably a good reason why you didn’t buy it,” she says. This is akin to an age-old marketing maxim—“timing is everything”—that Tucker says is being lost in the digital age.”
See also this article for similar evidence that personalization in general can become too personal or not personal enough:
Can personalization get too personal?