I post regularly on Facebook, I don't lead a very interesting life, I am a sahm to a toddler.
I have friends who are doing amazing things in far flungplaces, I don't think you need to be leading an interesting life to post on facebook.
I live in a different country and I find Facebook helps to create the feeling of a more everyday relationship, I'm not going to phone my mum up and tell her ds has learnt to jump or that we went to the zoo but she can see on facebook the little things we do, the same for all my family.