Using "M" is as simple as beginning a conversation with the assistant through the Messenger app, at which point it will begin providing you with recommendations or ask further questions to narrow down your request. Unlike Siri, "M" does not have a gender, nor it is possible to know whether you are being helped by a bot or a real Facebook employee -- but Facebook aims to make sure that every request is answered.
"M" aims to take on Siri, Google Now, Cortana and a growing selection of virtual assistants as the "first stop for anyone looking to do or buy anything":
It won’t take long for Messenger’s users to realize M can accomplish much more than your standard digital helper, suspects David Marcus, vice president of messaging products at Facebook. “It can perform tasks that none of the others can,” Marcus says. That’s because, in addition to using artificial intelligence to complete its tasks, M is powered by actual people.Marcus believes that "M" will slowly expand beyond the Bay Area and eventually reach all of Messenger's 700 million users around the world.
Facebook Messenger [Direct Link] is free on the App Store for iPhone.