the "404" error page
It would be great if Duolingo could remove Immersion articles that violate copyright, rather than simply keeping them and tagging them with the "404" error message. This problem is especially evident in the English to Spanish Immersion section. It is frustrating to click on so many articles, only to find that they are not available.
? 404 Duolingo can not tag things 404 that are not under their control. They can not remove bad links, if no one tells them they are bad.
From wiki article:
The 404 or Not Found error message is a Hypertext Transfer Protocol (HTTP) standard response code, in computer network communications, to indicate that the client was able to communicate with a given server, but the server could not find what was requested.
The web site hosting server will typically generate a "404 Not Found" web page when a user attempts to follow a broken or dead link; hence the 404 error is one of the most recognizable errors encountered on the World Wide Web.