Hi,

How do they work? Classes are added to the DIV post? I see nothing different in the code or the frontend ...

Sticky posts are kept at the top of the news loop on page 1. Stickies on top are always the top of any other stickies.

If you want to style sticky posts differently you can use the function is_sticky() to check that. Please see the correct spelling of that function on the documentation I don't remember it offhand.