I have got a handful of Facebook Friends who are also friends, or ex boyfrends of my daughters. The latter because I became friends with their parents many years ago, buttheir parents do not have Facebook pages of their own, so its a way of keeping up with their family news. My Daughters are fine about it, my eldest one still chats to her ex from her teenage years, even though they are now both married with families of their own.
I also belong to a group from my old school, again photos and news is shared, and occasionaly some of them meet up for a night out. I once did this, but never again, People can change so much over the years, and the nice guy from the Youth club when you were 16, can be the Preditor from hell who thinks hes 'Gods gift to all women ' at 40!