- First of all, this page is fantastic. Kudos WAID. (Brb, going on a binge-read of the oldest archives. Okay, too much stuff there.)
- Some interesting threads:
- Undated Magnus quote from pre-November 2001: "Since my PHP script is the cause of this discussion, I should say that the script supports a "talk:" namespace for each topic. So, Talk:HomePage would be the talk "subpage" of HomePage. No need to keep subpages just because of the /Talk thing." (When did the referenced PHP script get deployed, I wonder?)
- March 2002: Magnus announcing "You can now sign with automatic (server) date using ~~~~ (4x "~")." (I think three-tilde was available before?) Looking at the oldest archives of enwiki's Village pump and Main page talk page, it looks like it took many months for it to really catch on, between earliest uses and widespread use.
- (It looks like, in general, basic info didn't make its way around very quickly at the time, possibly due to less communicative-/meta-efforts in general. I'm amused by this thread from February 2003, about the "pipe trick". Jimmy Wales and Anthere both didn't know about it, and even Brion Vibber didn't know about it for six months.)
- Fun fact: The earliest now-available revision of Main page talk page is Chuck Smith (in January 2002) telling someone they can sign their posts with three tildes.
- Erik Moeller talking about talk features being developed in January 2003: "You will notice that every user, anonymous or not, now has a "Talk" link behind their username in the Recent Changes list. In the case of anons, this leads to a page Talk:123.123.123.123 (IP address). Both anons and signed in users get a notification if their talk page has been changed. Instead of the old "Talk*" link, this is now a text message stating "You have new messages", linking to the talk page."
- Might be worth mentioning some bots in particular. HagermanBot (Sinebot's predecessor) was approved in December 2006, and was probably pretty impactful I would guess.
- In 2010, there was a bunch of discussion around LQT. (I started a successful vote on English Wiktionary to enable it, which was done in May 2010. As it turns out, I was completely wrong about how invested the WMF was into this, and a lot of other people were quite right.)
- Jorm put together some design docs about LQT3 around then: LiquidThreads 3.0/Design had interesting designs, one in August 2010 and another January 2011, in different styles.
- A few other communication systems, which may or may not count as "discussion tools": The Article feedback Tool, and the MoodBar. (Moodbar may have had a system for discussing feedback? Or at least, it did in the design doc. I don't recall ever actually using the system while it was around myself, so I can't confirm if it was in production.)
Topic on Talk:Talk pages consultation 2019/Discussion tools in the past
"Since my PHP script is the cause of this discussion".. this was likely Phase II, released 25 januari 2002. Before that time, Wikipedia used perl. In mid-end 2002 we had Phase III, known since half 2003 as MediaWiki.
I made a few updates. I'd be happy if you added the rest of this.
I saw MoodBar in action; it allowed editors to post a message. I don't remember using any built-in method for further discussion, but Feedback Dashboard/Phase 1 says that you could post a message to the new editor's User_talk: page from inside MoodBar (somewhat similar to Twinkle, from the appearance).
The problem with Moodbar and Article feedback was mostly that it generated posts, but posts that bypassed the watchlist and review/spam protection systems. As such they became very unpopular. This is one of the reasons that Flow did actually use those.