If you'll recall, both companies faced and continue to battle lawsuits regarding their drivers' status. In California, a number of contractors filed a class action suit in their quest to be recognized as employees. Anyone who wants to continue driving for either company has to register within 30 days of receiving the letter. Part of the missive says "Failure to respond... may result in penalties and payment obligations." They can file for an application through San Francisco's newly launched online business registration system.

In a statement sent to SFGate, Uber says that as independent contractors, its drivers "are responsible for following appropriate local requirements." Lyft spokesperson Chealsea Wilson, however, didn't bother hiding her company's issue with the new requirement. "We have serious concerns with the city's plan to collect and display Lyft drivers' personal information in a publicly available database," she told the publication. "People in San Francisco, who are choosing to drive with Lyft to help make ends meet, shouldn't have to compromise their privacy in order to share a ride."