Mark unread???

[Van, Arkansas, USA]

What does "mark unread" mean or do?  That small option at the bottom right of a post.
Blessings

[Robo]

When you view a post, the forum keeps track of that.  If you click on the New Posts at the top left of the website you will see your new (unread) posts.   If you "mark unread" a post the forum puts it back on your list of posts you haven't viewed.

https://wiki.simplemachines.org/smf/Unread_posts