I am a Skype user and not a FB user and I have no intentions of ever using the FB product again (I deleted my account around 2 years ago). I wonder how many of those 750 are the same as I.
Refs:
http://techcrunch.com/2010/11/10/dear-tech-press-lets-cut-th...
http://www.insidefacebook.com/2011/07/06/facebook-750-millio...
I still find some pets and companies using profiles, but most of these are pages these days (since there really aren't advantages to making a profile vs. a page for them), and there is a process for converting these to pages - https://www.facebook.com/help/?page=18918 - and it is the way to reactivate a non-human account that is reported.