Google’s top ad executive, Sridhar Ramaswamy, is leaving to join Greylock Partners as a venture partner. “Prabhakar Raghavan, head of Google’s business-applications unit, will step into the role on Friday,” Bloomberg reports. “Raghavan will now oversee product and engineering for the world’s largest digital-ads business, which is on course to generate more than $100 billion in sales this year.”