Ghostscripts

I once read a short story about an old man who still sat on the park bench he used to share with wife, having the same argument as always, except that her part was played by a recording made while his wife was still alive.

The idea is to record most living people, probably in 3D or holographic film, for when hologram technology takes off, talking about a large number of topics, prompted or unprompted.

After their death, video of them sitting or standing silently is projected perpetually onto a suitably sized gravestone. When you enter the cemetery and see thousands of people patiently waiting, you can talk to any one of them, and their responses are instigated by voice activators which look up recordings by topic keyword or synonym.

Just as valuable to have the anonymous swarm finally put their lives into meaningful order while they can still listen to their own advice.