Do you or does anyone else know of free online services, analogous to mailing lists, that allow such nesting and upvoting/downvoting?
Reddit. If you create your own subreddit I know you get to moderate it, but I don't know how well it would work for a deliberately exclusive community.
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: