The author joined Facebook in 2005 as one of the first members of the company's nascent customer-relations team. It was just a year since Mark Zuckerberg had moved Facebook's headquarters from his Harvard dorm room to California. When she arrived, there were 50 employees working from a small office in downtown Palo Alto, and the collegiate culture remained thick. Here is some of what she remembers from those days.

At 11 a.m. on my first day at Facebook, the young, plain-looking...