I will say that if you are organizing an event on Facebook, and you actually have a list of people you'd like to see there or who should be there, then if you d

I will say that if you are organizing an event on Facebook, and you actually have a list of people you'd like to see there or who should be there, then if you don't make an effort to contact the non-FB people, you're a bit of a jackass. We put together a big list of people for a HS reunion, and used real-life social networks to (try to) reach the names that weren't on FB. Mostly successful and with a large nucleus who were on FB, easy to distribute the workload.