often, yearbooks are distributed at the end of a school year to allow members to get the books and signatures/personal messages from classmates. in the us, those that distribute at this time may publish a supplemental insert with photographs from spring sports and milestone events (such as prom and graduation), as well as other important events. many schools at which yearbooks are distributed at or before the end of a school year have a tradition of having students sign and leave notes on each others yearbooks.