No, Facebook isn’t using your phone to eavesdrop on your conversations - but it is tracking you online

Kelli Burns may go down in history - or at least in Google search - as the professor who claimed, definitively, that Facebook “eavesdrops” on its mobile users.
Her comments, reported in a Tampa TV news segment two weeks ago, have sparked a global panic about corporate surveillance and personal privacy. The claim that Facebook is always logging the ambient audio from your iPhone or Android mic has been repeated everywhere from Pakistan to Armenia.
There’s only one problem: Burns, a communications professor at the University of South Florida, never said that. In fact, she doesn’t believe that Facebook is “spying” on anyone’s calls.

To Burns’s credit, she didn’t originate this particular rumour - it’s more fair to say she inflamed it. For years, everyone from Reddit users to Atlantic magazine writers have reported sensing something fishy about the timing of certain Facebook ads. Users report seeing ads for obscure things not long after mentioning them in conversation, which has led some to believe that Facebook surfaced those ads because it was listening in.
But when WFLA, a Tampa news station, ran a segment on Burns, in which she acted out the very same sort of scenario, people took it as proof positive: Facebook must be Big Brother.