Go here with your browser of choice. Depending on your browser's interpretation of the backslash character, you will be taken to one of two pages.
On a separate topic, follow this
link with your browser of
choice (please note that this contains a space and is actually an illegal
URL, even if your browser has rewritten it to be standards-compliant). Lynx is
notorious for not rewriting hrefs, and thus confusing the server.
Now compare/contrast the result with what happens when you follow this link, which contains a space
escaped as '%20'.
What do you do when you see URLs in a plain-text medium, such as Usenet - in particular, when they appear within sentences? Consider the URL http://theanna.org/slash/dot. URLs of that type being particularly problematic... Try that URL out and see for yourself.
For other stuff on the site, please go here.