I spent a lot of time thinking about this. When I was younger, I went to summer camp. I got letters from some of the kids, and I always wrote back because my mom said you have to send a letter to get a letter. I haven't heard from any of my camp friends in years. I seriously doubt that we have anything in common now though.
I don't necessarily think any more that continued contact makes friendships grow. I think it is love. With out mutual love, you won't keep in touch and you won't share.
With my closest friends it is not just the things we have in common, or how often we see each other. It is we truly care about each other.
What do you all think?