Of the myriad instant messaging services out there, Facebook Messenger is perhaps the most common and, therefore, most taken for granted. It doesn't usually make it to the headlines, except for the few times it manages to piss people off. Or gets an experimental and frighteningly smart feature. Or goes down, which is when people realize how embedded it has been in their digital lifestyles. Some changes, however, might be coming again to Facebook Messenger that could put it back in the spotlight, starting with the return of SMS.