I’ve done a search on this and I know that SDMB (or vBulletin) doesn’t know or care which threads I’ve actually read. It’s all to do with the last time I visited the board.
When I log on, though, it’s first thing in the morning here when there are loads of new posts having been posted overnight. Some days it can take me over an hour to catch up with the threads I’ve been following and the read/unread function seems to work.
Today, as is usual, there are lots of new posts to read but the whole board switched from ‘unread’ to ‘read’ in the space of about fifteen minutes.
What I’m really asking is: how long do I have to read and catch up with all the SDMB ‘news’ before the board decides to switch everything over to ‘read’?