Wow. The wiki has seen a lot of different things. It's so unfortunate that nobody was really cataloging it, see how the wiki has changed over-time. Well that is why I'm making this. Observe and document the major events (trends) going on in the wiki. I don't remember all of them since I had joined in February, 2017. But I will try my best.
The Beginning (April 2nd, 2016)
The Nin10do Era (April 28th, 2016 - Unknown End Date)
After a few weeks following the creation of the wiki, a user known as Nin10doGMod appeared on the wiki, and soon began to truly create the wiki. He spent time creating pages on the most popular AUs, such as Underfell and Underswap, and creating the most useful Templates still used today.
Massive gap of Unknown
Alphasaith Joins the Wiki February 5th, 2017
The Canon to story strikes (February 3rd, 2017 - February 22nd, 2017)
The event which I all the "canon to story strikes" was an event done by Phoebe Fennekin about whether something on any page was canon to one's story or not. The main target of these "strikes" tended to be UnderHell Sans, though there were other targets. Because of these "strikes" done by Phoebe Fennekin, a number of things were changed, like the story of Happytale. The "strikes" ended when Alphasaith confronted Phoebe Fennekin on her message wall and told her to stop.
UTAUWikiTale Arc (February 25th, 2017 - March 25th, 2017)
The UTAUWikiTale was an interesting premise, taking the Wiki by storm for ~a week. It was an idea proposed by UndertaleAUwikipersonandthings, or WikiP for short. The premise of UTAUWikiTale is all the monsters are replaced by users. WikiP eventually got overwhelmed by the popularity of UTAUWikiTale and handed it down to LunaDeaminac. Luna was then promoted to bureaucrat. After everyone had eventually done whatever with UTAUWikiTale, the popularity got toned down a lot, ending the trend or arc.
The Demotion of UndertaleAUwikipersonandthings (March 20th, 2017 - March 22nd, 2017)
The trend to get WikiP demoted may have lasted for only a few days, but it had a lasting memory on those that were in the debate. It was highly reminiscent of a propaganda war. Starting when Createsans wanted to get WikiP demoted for numerous reasons, it eventually ended when a lot of users supported not supporting Createsans. The one that I would credit as the one that ended the conflict is Cheeseskates. The blog page was deleted by Createsans soon after Cheeseskates made their case, as such, you can find the page the debate took place here.
The Kkone wave (April 1st, 2017 - April 8th, 2017)
The Kkone wave was a relatively large phenomenon within the chat part of the community. It started when Bone Apetit had made the joke ship to torture Kkcantgetright7. After a few days of torture for Kkcantgetright7, they seemed to embrace it. It finally died when people stopped focusing on it.
Chat Moderator Demotion (April 10th, 2017 - April 28th, 2017)
Beginning when some people began complaining that there were too many Chat Moderators. It eventually got to the point that LunaDeaminac got involved and made a poll so people could list the Chat Moderators that they wanted too keep. (Results when it finishes.)
The UTAUWikiTale ripoffs (April 22th, 2017 - April 24th, 2017)
A while back, UndertaleAUwikiPersonandthings had made an AU known as UTAUWikiTale. UTAUWT eventually became very popular. So popular in fact that if you haven't heard about it, then you are in the minority. Eventually, the roles for UTAUWT had been mostly picked, at least all of the "good ones", so people began creating their own UTAUWikiTale Ripoffs. A UTAUWTRO can be classified as an AU that has Users as the characters.
Large gap in archiving.
The Month of WikiP Demotion Polls (June 2017)
This month contains most of the WikiP demotion polls. Each of which failed.
New Theme Push (June 6th, 2017 - June 9th, 2017)
(Corruption in Archiving. Come back later.)
The New Era Setup (June 7th, 2017 - July 17th, 2017 @ 9:08 AM UTC)
The New Era Setup is an operation devised by Alphasaith to bring about a New Era of perfection on the wikia. The operation was announced almost a month after it began, on 7/5/2017. It ended with the successful demotion of UndertaleAUwikipersonandthings.
The Tournament (June 25th, 2017 - August 7, 2017)
The Tournament was a battle arena-type thing created by TheDarkestDecent.
WikiT hate period (Beginning date Unknown - 7/13/17)
This stretch of time contains the most amount of hate for Wiki Temmie.
The New Era (July 18th, 2017 @ 12:41 AM UTC)
The New Era began when the user UndertaleAUwikipersonandthings was demoted from the position of Bureaucrat.
The Wiki Wipe (August 7th, 2017 - November 3, 2017)
The Wiki Wipe is the act of cleansing all the undesirable & N/A pages from the UTAUWiki. The total number of pages went from ~2700 to ~800.
The Survivor Standardization (November 3, 2017 - Present)
The Survivor Standardization is the act of standardizing all surviving pages from the Wiki Wipe.
The Combination War (July 21st, 2017 - July 23rd, 2017)
TBA (Yes, I know calling it a war isn't accurate, but it makes it sound interesting, that and I didn't have a different creative name for it, and no I won't be changing it.)
Large gap in archiving.
First anniversary of Alphasaith joining the Wiki (February 5, 2018).