A Cornell researcher finds that before diaries became private and personal, people would share their daily entries in the same way we use personal blogs and Twitter today:
[T]hrough her research, [Lee] Humphreys found that it’s only been in the last hundred years that journalling has come to be considered a private practice. In the late 19th century, she says visiting friends and relatives would gather together and read each others diaries as a way of keeping up to date and sharing their lives. Journals were also kept in early American towns to mark and record important events: weddings, births, deaths and other events of community-wide importance.
“You don’t get a real sense of personal, individual self until the end of the 19th century,” Humphreys told the Cornell Chronicle in 2010, “so it makes perfect sense that diaries or journals prior to that time were much more social in nature.”