I would love to make a wiki (there are lots of options for wiki templates that can be downloaded and hosted) to go document ways to have a discussion online. It would document all sorts of possible features, link to examples in use (like how you mentioned slashdot) it would document serious problems each feature tends to bring, and possible solutions. From there, it would list programs in place that can be used now liki phpbb and the reddit template this site uses, and then also the end goal for the wiki for me I think would be to start a large open source project/s that anyone could use separately, and fork and change at will. Im too busy to set that up, but i would happily contribute to it.

I want to see a large number of thriving communites separate from each other, but perhaps linked. Not as linked as reddit is though, I would want the control to be decentralized completely. At the bottom of this comment I link to a couple of sites, I think one of them has decentralized nodes.

My posts on reddit

https://www.reddit.com/r/C_S_T/comments/4sjv6s/internet_forums_part_1_every_part_of_how_a_forum/?st=izv6yxeh&sh=00251547

https://www.reddit.com/r/C_S_T/comments/4tjsxz/internet_forums_part_2_reddits_design_influences/?st=izv6xoqs&sh=d018b3f4

https://www.reddit.com/r/C_S_T/comments/5xmhe4/internet_forums_part_3_if_c_s_t_didnt_exist_but/?st=ja7i378p&sh=08b224b2

Relavent subs:

https://www.reddit.com/r/TheoryOfReddit/

https://www.reddit.com/r/ModerationTheory/

Other websites

http://friendi.ca/

https://diasporafoundation.org