GumGum is a company whose platform serves up online ads related to the context in which potential customers are already shopping or searching. (For instance: it will send ads for Zurich restaurants to someone who’s booked travel to Switzerland.) To handle that granular targeting, it relies on its proprietary machine learning platform, Verity. “For all of our publishers, we send a list of URLs to Verity,” according to Keith Sader, GumGum’s director of engineering. “Verity goes in and basically categorizes those URLs as different [internal bus] categories. So the IB has tons of taxonomies...