Once you pass the age of, say, 30, you have enough friends, right? But if you don't have children, you occasionally let a new friends into the fold, one that you really enjoy the company of. By the same token, you cut other friends, realsing that people who make you feel stressed or depressed are not worth the emotional effort.
But when you have kids, that changes. You have to, are forced to, make new friends. Other people with kids, that live locally. I have plenty of friends, but most of them live in London, Australia and South Africa. We email, text, talk on skype and occasionally meet up. But now I have a 2 year old boy and I was forced to make friends with Local Mothers. It feels strange to me - I know I wouldn't be friends with these ladies if it wasn't for the fact that we have children the same age, and happened to attend the same baby group/toddler group. Not that there's anything at all wrong with them. They're really nice people. But we don't click on a level that I do with my 'real' friends. We pleasant and polite, talk about kids, groups etc. Moan about our husbands, money, other stuff. Basically go through the motions so my child has some local friends.
IT sounds like I'm using them - I suppose I am in a way, but I do genuinely like the ones I choose to hang out with. If anything, my main Local Mother friend uses me. Oh don't get me wrong, its a mutually beneficial relationship - but sometimes I realise that I was targeted by her for my semi-constant availability... not having any local family or friends, I am an available babysitter. She also doesn't have local family but set out to make friends in the area, started a couple of little businesses. She's very busy and highly productive (the opposite of me). But she did tell me how she targeted and ..attained some of her other friends and I can only assume she did the same with me.