For example, last year I got to meet maybe 30 friends from all over the world because they were passing through France or wanted to go travel to the country I was traveling to. I wouldn't have met them if they didn't have my facebook as I rarely keep touch with people far from me (before facebook). My mail is filled with spam and I change my number every year.
I also moved to a new city, didn't know anyone, joined the erasmus group and a few weeks after I knew 100+ people, was getting invited to parties every day, was meeting new people every day.
You can always try to avoid facebook, it will be more difficult though.
I move a lot, China, Canada, France these last years. I don't want to keep paying to keep my number, and I don't really care about changing my number, if people want to contact me they can always find me on facebook (I have everyone there), and the few that don't use a facebook, well I don't really keep in touch with them but I don't have time to track everybody.
