Friends from the past:
From kindergarten (in Adelaide): 0
From prep: have remained in scarce contact with 1
From grade 3 (a new primary school): good with 1, and have another few on Facebook
From high school: have most on Facebook, only keep up with 1
From MHS (year 9 onwards): have almost all of the year level on Facebook, keep up with the ones I see at university, and a group of ~10 in the summer
I still keep in touch with 1 friend from kinder in China
In one of my classes I also discovered a girl I knew in my first primary school and we hated each other but now we're friends

also keep in touch with another person from there
Still keep in touch with year 5/6 school friends, mostly through Facebook though I've run into a couple on the train / at uni
High school friends I'm still in regular contact with about 4, 2 of which I still consider my best friends and vice versa, the other 2 are also lovely people, but the majority of high school friends I only sometimes talk to when I see them around / on MSN / Facebook etc
... it's sad, I thought I'd stay in contact with more high school people