I’ve discovered that the Mark All Topics Read button works very nicely in the Off Topic forum. So long as the topic count stays reasonably low the response of that button is pretty fast. Sure beats scrolling through all “stuff” just to clear the New flag.
JR
Jon , I sympathise .
But I do like to read what people are saying , they have gone to the trouble of writing it . No need of a reply , unless you want a bit of fun .
Mike
So Jon, this is exciting, I go to “Off Topic” after reading everything else that is worthwhile and that option will show in the upper right hand corner of the screen. Nail that sucker and all the World is instantly better? If true, for that, I owe you another beer. Come on guys fill up that “Off Topic” thread, so I can try this baby out. 
How exciting, finally someone comes up with a solution. Thank you, Jon.
Ok , chaps , where is this "mark as read " thing hidden ? Blowed if I can see it . Perhaps I read it one time and marked it as read . Mmmmm .
In the forum view (not inside a thread), top right of your screen, just below the menu / banner ad.
Works great 
Bob finally got it working? Cool!
Righto , Jon , I found it . Thanks for that , I do read most threads , but find the Conventions and so on a bit upsetting 'cos I can’t get to them .
One day , one day .
I read them and wish , “if only”
But all my rich aunts are long gone , so I shall have to ask for intervention from the great lottery ticket wizard in the sky .
Mike