Facebook has talked about the ability to switch user accounts to "memorial" pages when someone dies, or delete them, depending on the preferences of next of kin. I haven't really thought about this or noticed it affecting me in any way, but they must have just done something that caused a status change on those users so they show up as inactive. Apparently I have seven Facebook friends who have died, and their profile pages now say "Remembering ____." A little jarring.
Actually, make that eight. There's a recent "departure" who doesn't appear on the list yet.
It's interesting to see how people "interact" with dead friends on Facebook, including birthday messages remembering them. Writing on someone's wall is the modern equivalent of talking to their gravestone, I guess.