We know Zuck was close to Adam D'Angelo. They went to High School together and even built the digital music software that first igniting Zuckerberg's entrepreneurial imagination back in his teens. Cohler was employee number five at Facebook — there when the company was one room big. Zuck recruited Hammerbacher, whom he knew from Harvard, to join the company from a presumably well-paying gig at Bear Stearns. With all his friends leaving, oon Zuckerberg won't have any Woz- or Allen-like buddy at the company.