Elon Musk.LUDOVIC MARIN/POOL/AFP via Getty Images Elon Musk announced last month he'd found a replacement for the Twitter CEO role. Linda Yaccarino, a former NBCU ad sales chief, said she started the job Monday. She began two weeks ahead of schedule, with Twitter's ad business currently struggling. Elon Musk is no longer the CEO of Twitter, as Linda Yaccarino started at the company on Monday.Around 8 p.m.