By chance or nature's changing course untrimmed

What if someone died that was a friend of mine, or yours, or anybody's, through the Internet, through, as Shakespeare put it, "by chance or nature's changing course untrimmed"? How would we know of it? Would anyone be able to find out all of the many accounts that that person may have on so many different websites to let all of those friends know? Would it be possible? Would the remaining friends or relatives of the deceased person care?
O what a tangled web we weave...