The Fallible Ideas discussion group is currently active (link) and discusses philosophy and its implications, especially the ideas of Elliot Temple, David Deutsch, Karl Popper and Ayn Rand. The discussion group started in 2013 and this archive goes up to March 2018.
There's a ton of content here. Don't try to read it straight through. Skip parts that don't interest you, skim for parts you like, or search for keywords to find specific topics you want to learn about. This short video tutorial explains the best way to search. Also, text is frequently repeated because people quote what they're replying to. If you remember what a quote says, there's no need to reread it.
Note: The PDF is very large (66,441 pages). It works fine with Adobe Acrobat Reader. Don't try to open it in Preview, and it may not work well on mobile.
The Beginning of Infinity is a book by David Deutsch. The discussion group studied and analyzed its philosophy and implications from 2011 to 2017.
Note: The PDF is very large (18,493 pages). See the note in the Fallible Ideas section above, and the advice there about not reading straight through.