We did something similar that in middle and high school.
There were two basic versions.
1) Done the last week of classes for the year, a blank notebook with the owners name in the inside cover is passed around, much like an annual, and everyone signs and writes well wishes or last minute number exchanges, etc.
2) Done at any time during the year, a blank notebook with no names is passed between a small clique of friends where notes, questions, gossip, and plans are exchanged. It had either set or nebulous protocols as to who gets it when and for how long depending on the group of a girls and an unwritten rule that if you come into possession of another cliques book you return it without drama or snooping. The book, by the end of the year is a collection of notes and pictures and memories of the year.
If it would make a decent coffee table book or at least be safe in a home environment and not crumble I'd probably keep it. But then this from the girl who still has to go through the attic. I'm probably bad about keeping things that really aren't worth it.