From the MozillaZine FAQ:

Q: What are Sticky topics?
A: Sticky topics appear below any announcements in viewforum and only on the first page. They are often quite important so you should read them where possible. As with announcements the board administrator determines what permissions are required to post sticky topics in each forum.

It looks that "sticky" nodes are posts deemed worthy (by moderators) to be promoted to headline status. The closest parallel I can draw to PerlMonks site is "Frontpaging".

Update: Also take a look at Categorized Questions and Answers section.