Also, there are two forum settings:
Visit timeout: Number of seconds a user must be idle before his/hers last visit data is updated (primarily affects new message indicators). (60 minutes)
Online timeout: Number of seconds a user must be idle before being removed from the online users list...
More info here: https://www.backyardchickens.com/forum/viewtopic.php?id=11055
"If you logoff or if you remain inactive for over 60 minutes all the posts that were new BEFORE you logged off or BEFORE you went idle will automatically be marked as read. Fortunately any new posts that people make...