The exact nature of what Rosenberg is doing is under wraps, to no one's surprise, but he's expected to guide engineers as they craft "large-scale" object detection algorithms. Before Google, he worked at HP Labs and was one of iRobot's earliest employees.

While it might seem odd for Rosenberg to switch employers while Google is still pushing the boundaries of AI, it's easy to see why Pinterest would want to reel him in. He's joining right as the company's AI-based image recognition is hitting its stride -- there are now over 300 million visual searches every month, or a 70 percent increase compared to a year earlier. Rosenberg could prove instrumental to keeping that momentum going, and could make Pinterest indispensable the next time you need to find a recipe or choose an outfit.