As Melissa Harris-Perry walks off MSNBC show, speculation erupts on Twitter

MSNBC host Melissa Harris-Perry sent an e-mail to staffers of her show on Friday, informing them that she had no intention of going on the air as scheduled Saturday morning.For weeks, her regular weekend show, she wrote, had been preempted by election coverage, raising questions from viewers and media critics about her absence. What's more, she added, "Social media has noted the dramatic change in editorial tone and racial composition of MSNBC's on-air coverage."