OCCUPATION: Google good guy
PREVIOUS APPEARANCES ON THE TIME 100: 1
PRO: During his three-year stint as head of the philanthropic group Google.org, Brilliant oversaw such projects as the disease-tracking Google Flu Trends and a home-energy monitor called PowerMeter.
CON: In February, he announced he was stepping down from his Google.org post. He'll stay with the company, but experts expect Google's philanthropic investments to shift toward technology-enabling causes.