AGE: 23
OCCUPATION: Founder and president of Facebook
NUMBER OF TIME COVERS: 0
PREVIOUS APPEARANCES ON THE TIME 100: 0
PRO: Forbes has him as the youngest self-made billionaire in history, and his success has drawn easy comparisons to fellow Harvard dropout Bill Gates. Vowing to stay independent, he's turned down billion- and near-billion-dollar offers from Yahoo and Viacom — but allowed Microsoft a 1.6% stake, boosting the privately held company's perceived worth.
CON: Facebook's "Beacon" ad-tracking system drew fire from privacy advocates and users, who were shocked to learn that Facebook was monitoring members' Internet activity on and off the site. And Zuckerberg keeps getting poked by lawsuits and controversies surrounding Facebook's origins. So send him a "hug."