It might have been useful a few years ago, but nowadays it makes no sense anymore.
I have to partially disagree on this. I find it quite useful for finding threads that need to be reported (not that much recently but still has its purpose).
- Having said that, I prefer if there was an option for enabling/disabling it (like for "Patrol" link) on "Forum Profile Information" page.
Now, even that doesn't make much sense because most threads are just useless.
I agree with the OP. "Show unread posts" is pretty useless now that the forum is so cluttered.
Ignoring certain boards that contain useless/uninteresting threads, is the key (after modifying the "Ignore Boards Preferences", you'll find "Show unread posts since last visit." option to be "less annoying".
I haven't posted in the Wall Observer thread in 2-3 years, but it's still always at the top. Same with a few other megathreads.
Having a new "ignore" option for viewing threads on "Show unread posts since last visit." page, can come in handy.