Sharing the minutiae
Many of my closest friendships have been formed through just the everyday stuff. What might be considered minutiae. Counting the number of feeds we'd done with our newborns the night before (trying to stoically ignore those women with the baby that 'just sleeps through from 8-6 without a feed'), retelling the trauma of a two year old's tantrum in the shopping centre, trying to find shoes that fit our toddler's weird feet, analysing the distance the vomit projectile travelled during the latest round of family gastro, negotiating lifts to netball training, bemoaning another round of nit treatment.
I just think that facebook is another form of this exchange of information. It doesn't always have to be negative. It might be something funny your kid has done. Or an anniversary you're celebrating. Or a failure that helps others realise that you're just normal like them (my area of speciality).
And that's it really. Our best relationships are with people who make us feel less alone - we're not meant to be living life in isolation. We're meant to share life. And facebook and other online forums let us do that. Not all bad.