““Ofer Sharone, a professor at MIT’s Sloan School of Management, says some of these new services create wonderful opportunities for the underemployed and long-term unemployed. “If you’re looking for a way to survive, they can be helpful.’’ But, he acknowledges, they are “threatening to people who are doing OK with the status quo, like a taxi driver or bed-and-breakfast owner who has invested a lot and suddenly is competing with Uber or Airbnb.””