Today's post, For The People Who Are Still Alive was originally published on 14 December 2008. A summary (taken from the LW wiki):

Given that we live in a big universe, and that we can't actually determine whether or not a particular person exists (because they will exist anyway in some other Hubble volume or Everett branch), then it makes more sense to care about whether or not people we can influence are having happy lives, than about whether certain people exist in our own local area.

Discuss the post here (rather than in the comments to the original post).

This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was You Only Live Twice, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.

Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.