The little saying ‘go to the first unread post’ is sometimes there and other times it isn’t. Is there a particular similiarity that I’m too dim to notice? It has happened when I’ve visited the thread before and am checking for new replies and it’s NOT been there on the same thread but just at another time.
Just curious. It’s a nice feature. 
I don’t know how much help I can be on this, but it seems that most of the things like the color of the envelopes & the dots on the forums page are based on your “last visit” time. This is at the top of the main forums list page, where it says “Welcome back Anti Pro, you last visited at ???”. That time seems to set the stage for the colors and the presents of the “go to the first unread post” link.
There is another thing that goes on also. There is some kind of automatic logout/login after a certain period of time. I think it is about 45 minutes.
So, you may start reading stuff, a little while later check back and everything’s changed and you have never actually left the board. But if you go back to the main forum list page, you’ll see that your last visit time has changed.
I’m sure this is more than you wanted to know about it and it may not be accurate, but I think it’s pretty close.
Jim
You are a true gentleman and a scholar, Jim! Thanks, that does help!
I really like that feature, I’m still stumbling over the quote/profile/ selection being on the bottom. I’ve reached a few times now for the wrong person. Old dogs being taught new tricks, and all that! 
Just trying to help.
Jim