So Mozilla has a new browser add-on for Firefox called Test Pilot, which displays a link to the Wayback Machine whenever a user hits a 404 page. Basically, a user finds a 404 and says to themselves "Oh, bummer. Where will I find that content now?" Mozilla replies, "Why, HERE! Try the Wayback Machine to retrieve an old version of the page!" and the user goes to check it out. This is an add-on, do note. One needs to opt-in to use it, and it doesn't come standard with any version of Firefox anymore. Still, the fact that it's an "official" test add-on has some webmasters worried about Mozilla's intent and direction as a company.
The conflict here is that a 404 is created by a webmaster for a reason. So even if the user is happy to discover an older version of the content, it may have been made unavailable in the first place for good reason. So what's more important? Satisfying a user's desire to find a specific piece of content or the intent of the 404?
"404 exists for a reason. This time the boffins at Mozilla have sniffed too much cat nip!" tangor writes on WebmasterWorld. "Firefox doesn't know the difference between 404 and 410? This is worrying," lucy24 writes. "This is simplyl stupid. My sites return a special 404 page with links to major parts of the site, search box, etc. This would defeat the purpose of it..." motorhaven writes.
But, as user bakedjake writes, "After having this installed for a bit I think this is probably great for users even though I hate it as a webmaster> The plugin was useful to me twice for non-webmaster reasons in the first hour I had it installed."
So it's useful to some, but could be rather damaging for others. You can get more details about how the plugin functions and when it prompts a Wayback Machine link, as well as read some very insightful responses, at the WebmasterWorld link above. Check it out!