Bots have become an increasingly effective way for users to interact with brands on Facebook, so Facebook Messenger ads seem to be a logical extension of that technology. The system, recently unveiled by Facebook, will let brands use bots to contact Facebook users directly through Messenger, in the same way that users already receive messages from their friends.
Facebook Messenger ads won't let brands simply contact everyone on the platform, however. Bots are automated, meaning that brands theoretically have no limit on the amount of messages they can send. Facebook has thus imposed an artificial limit, only letting brands send direct messages to users who have interacted with them on Facebook at some point in the past. Further, users have the option of blocking the message or account of brands that contact them.