404 Not Found
In one sentence
The server's answer that the requested resource does not exist.
Analogy Mental model
Walking to an address and finding an empty lot. The building that was there has been demolished.
In practice What you actually do
Monitor 404s in the page indexing report. When a URL with links or traffic disappears, redirect it to the closest equivalent. When nothing equivalent exists, let it 404 or 410 and stop linking to it.
Where people get burned Pitfalls
A custom error page offering only an apology is a dead end. Give it navigation and a search box, because the visitor arrived intending to be somewhere and the site still knows roughly where.
This entry was written in English from the Chinese original, not machine-translated. Read the Chinese version →