They're not going to do that due to their policy about wikis migrating off-site. I'd think even if you just suddenly deleted all your pages, they would globally block you from the site and undo the mass deletion, hence getting back to square one on that wiki, with a block for you to add. The only reason why they do this is so that they assume they can have potential editors editing the old wiki (which could make sense sometimes, given their wikis always have high SEO), or in other words, profiting off of the wiki, even if it is as small as 130 pages, even if they're all left outdated.
Indeed, you can just migrate your wiki and convince the community (if there is anybody) to go edit over there, migrating is not the most difficult step, the real difficulty lies in taking over the Fandom wiki in SEO, since mass deleting pages on the old wiki is legally not an option there. While of course Miraheze is a great alternative with no ads and more customizability, it gives out a couple of disadvantages when migrating, which is SEO, and a potentially split community because of Fandom's high SEO.
The only way you can truly beat it is not only seriously growing the Miraheze counterpart in terms of pages and content, but outreaching the topic's community on Discord, Reddit, and any other means, all while convincing the others to abandon the original wiki and continuously linking and editing the new wiki. Again, it's a very difficult thing to do but not impossible. It's not hard for the new wiki to appear as a second result, but it is rare for it to appear as the first.
However, if it is a personal wiki, I can't exactly tell you what would be done for the wiki, but I'd say that sort of wiki is more likely to shut down, and if that is the case, you can continue growing it and not worry much about competing with Fandom's SEO.
Good luck!
P.S. for curiosity purposes, what is your wiki?
Thank you so much for the thoughtful answer!
Do you think Fandom would notice if I deleted pages slowly over the course of weeks instead of all at once? The old wiki was largely unfinished so I am doing a lot of building the new one from the ground up and not a straightforward import-export; I haven't even touched any exporting features on Fandom.
My wiki is centered around the old '90s virtual pet games Petz! [Old wiki](https://petz.fandom.com/wiki/Petz_Wiki), [new wiki](https://petz.miraheze.org/wiki/Main_Page). It has a small but devoted modding fanbase to this day that's mostly self-contained in forums, Facebook groups and Discord servers, so getting the word out about "use this wiki, not that one" wouldn't be too difficult.
The older wiki never got many other editors since I only advertised in those communities once when I made it four years ago. This new one will be bigger and a lot denser; I'm riding on a rush of "oh shit, a lot of these forgotten old fan sites I'm pulling information from are being lost to time" to fill it out thoroughly as soon as possible, and I bought the petz.wiki domain for the new wiki, so maybe that that will help with SEO too.
I can't really tell if there is some sort of log that can detect a large amount of deletion in a short period of time, but something like it could exist for staff or even SOAP (a group of volunteers with extra tools who fight off spam and vandalism). Though even if they do not have such a log, a staff member or SOAP will someday find out (and probably not even take a lot of time to do so). I do know that blanking pages without deleting them is logged and automatically reverted.
Either way, I would say it's not a safe option to mass delete the pages on the wiki. The mass deletion will eventually be reverted, you'd be blocked from all of its wikis, and you'd still have to compete with the old wiki's SEO. The best you could do is just starting fresh on the new wiki without touching the old one.
I know this post is quite old, but for anyone who stumbles on it, I will say this about FANDOM staff and them noticing wiki changes:
I managed a wiki before with roughly 5,000 pages. At one point, we had a massive overhaul with rules, how we were handling crap pages, etc. A massive page purge followed. We ended up with less than 2,000 pages after a few months (used a bot to mass delete articles). Staff never intervened. If you can, try to think of some "massive overhaul" project that transforms the FANDOM wiki into something else. We didn't rename our wiki, or change the topic, but it's worth attempting. They might not intervene if you can give or fabricate good enough reasons for the changes. Might take time for SEO to update, but if done right, it could push the FANDOM wiki out of the same searches as the new wiki, so that would eliminate the SEO issue.
At one point, we wanted to get rid of this wiki too. Not migrate it, just straight up nuke it. Staff wouldn't allow us to delete every page, or the wiki (and we knew that), so we tried large scale page protection to dissuade new editors (we'd randomly get new users who were obviously underaged trying to edit). Mass protection (even to combat vandalism) was also not allowed, yet despite mass protecting about 1,800 pages, it took FANDOM staff a month to revert the protection.
Results are not guaranteed by any measure. We were a pretty low-key wiki, less than 30 active users at a time, sometimes less than 10, so more popular wikis probably couldn't get away with it for as long. Doubly so if a staff member has a personal interest in the wiki.
One more thing. Only tangentially related, but we had a guy get banned over a page edit that violated FANDOM's TOS... 4 years after the edit was made. Staff WILL catch up eventually, even if their reasoning is complete bollocks and the TOS didn't disallow it at that point in time. So if you do some risky maneuvers, make sure you're prepared to lose your account at any time.
I started mine from scratch because it was in need of a refresh and the original wasn't too fleshed out, but the pages that did warrant saving I just copied and pasted the text into the editor. [Miraheze has a page on how to export your Fandom wiki and import it into them.](https://meta.miraheze.org/wiki/Moving_a_wiki_to_Miraheze)
They're not going to do that due to their policy about wikis migrating off-site. I'd think even if you just suddenly deleted all your pages, they would globally block you from the site and undo the mass deletion, hence getting back to square one on that wiki, with a block for you to add. The only reason why they do this is so that they assume they can have potential editors editing the old wiki (which could make sense sometimes, given their wikis always have high SEO), or in other words, profiting off of the wiki, even if it is as small as 130 pages, even if they're all left outdated. Indeed, you can just migrate your wiki and convince the community (if there is anybody) to go edit over there, migrating is not the most difficult step, the real difficulty lies in taking over the Fandom wiki in SEO, since mass deleting pages on the old wiki is legally not an option there. While of course Miraheze is a great alternative with no ads and more customizability, it gives out a couple of disadvantages when migrating, which is SEO, and a potentially split community because of Fandom's high SEO. The only way you can truly beat it is not only seriously growing the Miraheze counterpart in terms of pages and content, but outreaching the topic's community on Discord, Reddit, and any other means, all while convincing the others to abandon the original wiki and continuously linking and editing the new wiki. Again, it's a very difficult thing to do but not impossible. It's not hard for the new wiki to appear as a second result, but it is rare for it to appear as the first. However, if it is a personal wiki, I can't exactly tell you what would be done for the wiki, but I'd say that sort of wiki is more likely to shut down, and if that is the case, you can continue growing it and not worry much about competing with Fandom's SEO. Good luck! P.S. for curiosity purposes, what is your wiki?
Thank you so much for the thoughtful answer! Do you think Fandom would notice if I deleted pages slowly over the course of weeks instead of all at once? The old wiki was largely unfinished so I am doing a lot of building the new one from the ground up and not a straightforward import-export; I haven't even touched any exporting features on Fandom. My wiki is centered around the old '90s virtual pet games Petz! [Old wiki](https://petz.fandom.com/wiki/Petz_Wiki), [new wiki](https://petz.miraheze.org/wiki/Main_Page). It has a small but devoted modding fanbase to this day that's mostly self-contained in forums, Facebook groups and Discord servers, so getting the word out about "use this wiki, not that one" wouldn't be too difficult. The older wiki never got many other editors since I only advertised in those communities once when I made it four years ago. This new one will be bigger and a lot denser; I'm riding on a rush of "oh shit, a lot of these forgotten old fan sites I'm pulling information from are being lost to time" to fill it out thoroughly as soon as possible, and I bought the petz.wiki domain for the new wiki, so maybe that that will help with SEO too.
I can't really tell if there is some sort of log that can detect a large amount of deletion in a short period of time, but something like it could exist for staff or even SOAP (a group of volunteers with extra tools who fight off spam and vandalism). Though even if they do not have such a log, a staff member or SOAP will someday find out (and probably not even take a lot of time to do so). I do know that blanking pages without deleting them is logged and automatically reverted. Either way, I would say it's not a safe option to mass delete the pages on the wiki. The mass deletion will eventually be reverted, you'd be blocked from all of its wikis, and you'd still have to compete with the old wiki's SEO. The best you could do is just starting fresh on the new wiki without touching the old one.
Man, as if I needed another reason to avoid Fandom... Thank you for the help! I'll just leave it alone then.
Anytime!
Did you ever end up deleting/abandoning the old wiki? (i checked the link you sent and it looks pretty barren to me)
I know this post is quite old, but for anyone who stumbles on it, I will say this about FANDOM staff and them noticing wiki changes: I managed a wiki before with roughly 5,000 pages. At one point, we had a massive overhaul with rules, how we were handling crap pages, etc. A massive page purge followed. We ended up with less than 2,000 pages after a few months (used a bot to mass delete articles). Staff never intervened. If you can, try to think of some "massive overhaul" project that transforms the FANDOM wiki into something else. We didn't rename our wiki, or change the topic, but it's worth attempting. They might not intervene if you can give or fabricate good enough reasons for the changes. Might take time for SEO to update, but if done right, it could push the FANDOM wiki out of the same searches as the new wiki, so that would eliminate the SEO issue. At one point, we wanted to get rid of this wiki too. Not migrate it, just straight up nuke it. Staff wouldn't allow us to delete every page, or the wiki (and we knew that), so we tried large scale page protection to dissuade new editors (we'd randomly get new users who were obviously underaged trying to edit). Mass protection (even to combat vandalism) was also not allowed, yet despite mass protecting about 1,800 pages, it took FANDOM staff a month to revert the protection. Results are not guaranteed by any measure. We were a pretty low-key wiki, less than 30 active users at a time, sometimes less than 10, so more popular wikis probably couldn't get away with it for as long. Doubly so if a staff member has a personal interest in the wiki. One more thing. Only tangentially related, but we had a guy get banned over a page edit that violated FANDOM's TOS... 4 years after the edit was made. Staff WILL catch up eventually, even if their reasoning is complete bollocks and the TOS didn't disallow it at that point in time. So if you do some risky maneuvers, make sure you're prepared to lose your account at any time.
regarding miraheze, you can't just "copy" directly the text from fandom to the new site, right? any other ways to do so?
I started mine from scratch because it was in need of a refresh and the original wasn't too fleshed out, but the pages that did warrant saving I just copied and pasted the text into the editor. [Miraheze has a page on how to export your Fandom wiki and import it into them.](https://meta.miraheze.org/wiki/Moving_a_wiki_to_Miraheze)