“Work of any meaningful substance is likely to require many disciplines, more than any one person can manage on their own. Some people are focused on building the feature itself. They are from disciplines such as research, engineering, and design. We often refer to these teams as vertical teams. Other people work across many products to ensure decisions made locally within the feature don’t cause a bad result for the rest of the product globally. They are from disciplines such as security, legal, and design (many disciplines are represented in both camps.) We refer to these teams as horizontal teams because they work across vertical teams.”