I can see the problem of a long list of sticky posts under "All discussions" page. These sticky posts might only be important when users look at a specific tag. I think it's better for these pinned post not to be pinned under "All discussions" page.
I understand that currently "sticky post" would no longer be sticky once it is read under "All discussions", but for non members/visitors, or for users that don't care about the sticky post, these "Unread stickies" would always appear on top of the "All discussions", which doesn't look good.
