Erin Griffith:

In some respects it’s impressive that Facebook kept M running as long as it did. Despite the hype, M, which lived in Facebook Messenger, was presented as an experiment. The free service was only offered to 10,000 people in the San Francisco area, who used it to do things like book restaurant reservations, change flights, send gifts, and wait on hold with customer service. For those that had access, M was a fantastic perk. But for Facebook, it was a cost center.

That’s because most of the tasks fulfilled by M required people. Facebook’s goal with M was to develop artificial-intelligence technology that could automate almost all of M’s tasks. But despite Facebook’s vast engineering resources, M fell short: One source familiar with the program estimates M never surpassed 30 percent automation. Last spring, M’s leaders admitted the problems they were trying to solve were more difficult than they’d initially realized.