What should you take into account when you create custom 404 (Not Found) error pages?
That's the question I just asked myself and did some "Google Research".
I got lots of results how you have to configure Apache or IIS, but that's not what I'm interested in.
Here are some results which cover what I want to know:
* Useful "Page not found" error pages
* Implementing Sensible 404 Pages With Apache