Jocelyn Goldfein:

Facebook’s struggle pivoting to mobile illustrates the potential for trouble. Facebook’s speedy, individualistic and iterative way of designing and shipping software was deeply embedded in product team culture. If you worked in the web tier, the cost of releasing was pretty close to zero and literally everything else about the way you worked was optimized to take advantage of that assumption. As the company’s focus shifted to native mobile apps, the engineers hired for their mobile expertise insisted on a heretofore unknown process like feature and UI freeze, functional specs and QA.