When a member of the community, or a popular figure in the hacker community passes away, a black bar is put at the top of HN in memory of that person.

Turning the orange bar at the top black. It's been done before as a sign of respect for other important people in the computing world who have passed.

PG has twice put a black bar above the top bar in memory of someone's death. See http://news.ycombinator.com/item?id=644954 for the first use of it, http://news.ycombinator.com/item?id=859117 for the second.

http://news.ycombinator.com/item?id=644954 It's a black bar across the top of the page. pg puts it up in memorial.

the red topbar is changed to black to show condolences.