AGE: 55
OCCUPATION: Internet entrepreneur
NUMBER OF TIME COVERS: 0
PREVIOUS APPEARANCES ON THE TIME 100: 1
PRO: As the founder of Craigslist, Newmark's remains one of the few remaining uber-traffic sites dedicated to public service and impervious to corporate overlords. Where else does a company founder still address customer service issues personally?
CON: As more and more companies enter the online classified market, how much longer can Craigslist sustain its current economic model?