I do see this as a good idea for some sections, including Perl News.

I don't see much use for it in Seekers of Perl Wisdom, Meditations, or many of the other sections. Perhaps it could be added only to those sections where it makes sense: Perl News, PerlMonks Discussion, and maybe even the Code Catacombs. In those sections, I can see where people might want to know about significant updates months after the original.

But when someone revises his month-old regexp parsing HTML question to ask it differently and clicks the "Significant Update" button, that doesn't mean I want to see it again, along with all of the now-out-of-context replies. ;)