Just before Facebooks initial public offering, its founder and CEO Mark Zuckerberg wrote a letter to investors reminding them that the social network was not originally created to be a company. He continued this trend internally, chiding employees who brought up questions about revenue during discussions of how to build new products. But according to a lengthy report in The Wall Street Journal, after a poor start on the stock market and a painful slide during his companys first two quarters, Zuckerberg decided to buckle down, grow up, and start focusing on the nitty-gritty of the business.