Spam. I think it queries facebook with random numbers until it comes up with a match. At that point it reads the name and sends the message with your name and a spam message.
I got a message from random area code saying hola and my name. So did my brother and my boyfriends mom. My brother does not have a facebook or number attached to facebook. I texted back asking who it was and no answer. So I called the number and the number was some texting app. Iam worried my info on my phone was hacked. I live in seattle. I heard this was on the news but I did not see it. A lot of people r getting these messages in seattle.