Facebook's new digital assistant 'M' will need to earn your trust

Just like Siri and Cortana, M will be fuelled by your personal data - this trust it expects must be earned and backed up by rules

Facebook's announcement that it is testing a digital assistant called "M" means that each of the "big five" technology companies is now in the digital assistant game. Facebook M joins Apple's venerable Siri app, along with Google Now and Microsoft's Cortana. Even Amazon has the Echo, a voice-activated internet of things appliance.

These assistants might revolutionise how we interact with our digital devices, our homes, and the world. They promise to effortlessly help us find, and even predict what we want. Facebook says M will make advances through leveraging its unmatched database of personal information, coupled with invisible human "trainers". By applying artificial intelligence to your Facebook data, M could help you buy gifts, book travel, and reserve tables at restaurants.