The napkin sketch was, well, a content prop for our site. That didn't actually happen.
When we first met with Mark [Zuckerberg] and Sean [Parker] to discuss the identity, Sean was leading most of the conversations. When Mark was brought into the project, he and Sean visited our office where Mark posed several questions about what our company did and what design was [to us]. For me to articulate an answer, I asked several questions of my own, such as, "Why did you make thefacebook.com blue?" and, "Why did you space the content like that?" He mentioned his colorblindness and he also said that he did what he could to "make it feel right." So, in his terms, I told him that as a design company we made things that "feel right to most people most of the time."
We hired our close friend and type designer Joe Kral of Testpilot Collective to finesse the logo mark and we then hired Peter Markatos (now of Markatos and Moore) to compose various stationary recommendations for their business cards, letterhead, etc.