Renaming and/or moving wiki pages is a good thing, but leaving a redirect is absolutely essential. Presumably this applies to all wikis, not just this one.
Moves & Renames = Good
Moving or renaming a page means you thought it would be better to have a different title, and changed it. Wikis thrive on, and indeed only exist because of, this kind of community involvement. Thank you! You have just helped to improve and evolve the wiki.
But Internets = Has Old Links
That being said, there's a lot of old stuff on the Internet. Out-dated XML Sitemaps, cached pages, mirrored pages, the Wayback Machine, pages not getting crawled as often as they should, etc. If you don't know what some of those things are, that's okay. The point is, if you move or rename a page without a redirect, all those sources will now just go to an empty page.
For example let's say the Google search results for "Example Page" haven't been updated in 3 months. We don't know why, but sometimes it happens. So if you renamed "Example Page" to "Awesome Example Page", without leaving a redirect, anyone who clicks on that Google search result will get a blank page and nowhere to go.
No Redirects = Bad
In the above example, this means they'll have to manually search for the new page on the wiki. I will be honest and say that I've never had much luck with wiki search. Maybe I'm just doing it wrong. But it never works as well as internet search engines for me. So the person in this case might run a search, and then not even find the page at all. This is bad. We want people to see pages, not get frustrated and lost trying to find them. Wikis should be oases of knowledge, not a search for the oasis in the Dry Desert Of Missing Redirects.
This is the page that inspired me to write this blog post. This is bad. What appears to have happened here is that I moved the page (I can confirm this part) and then the page was either moved or renamed again, but without a redirect. (I am assuming this part because I really can't know, since the page is gone).
That's really the crux of the issue. Without a redirect, we have no idea what to do next or where to look. We can run a search, but that doesn't always work out so great:
I don't know about you, but I'm not sure exactly which of those pages has the content from the old one. Maybe it's not even one page; maybe the old content is now in three different pages. I have to literally guess which is the new one, and hope I'm right. That's assuming I'm lucky and the new page even showed up in the search results at all.
In this case, there's more results farther down. So you're left skimming through 5-to-10 pages that may or may not be what you were originally looking for.
- Renaming pages is good.
- Moving pages is good.
- Leaving redirects is good.
- Choosing to not leave a redirect is BAD.