I really think all but a handful of HN readers first learned about Mirzakhani upon her passing. It's a tragic event -- highly so -- but not one of particular significance to this community.
I seem to recall feeling similarly a few times when we did have black bars. Sadly I don't remember who they were (which I suppose vaguely confirms what I'm saying?) but I do remember being surprised that I hadn't heard of them before, and didn't expect many had either.