http://www.w3.org/Provider/Style/URI.anything gives a menu of available extensions to choose from. For example, html.es for spanish.

However, http://www.w3.org/Provider/Style/URI/ does not work. I guess this makes some sense, but certainly violates the "typical" functionality on the web where trailing slashes are ignored.

Actually, this behavior you're referring to is a combination of trying to access a directory (to which a missing trailing slash is automatically appended) and the use of default pages (for Apache, that's the DirectoryIndex directive). Trailing slashes on files is not valid, because files are not directories.

Agreed. That’s a rule I mention in my piece, “URL as UI”, which I really want everyone to read. (If it feels like self-promotion, then please kindly ignore my username / blog masthead. I only care about these ideas.) http://alanhogan.com/url-as-ui

> Gracefully handle 404s.

> [...]

> Consider linking to your home page and/or site map [...]

For a second I thought you were advocating redirecting 404s to the homepage, and I was about to flame you. I hate that one, and I think it's harmful enough that you probably ought to have a point about not doing it in that article.

That's not true everywhere. For example, http://en.wikipedia.org/wiki/Wikipedia/.

Obviously it isn't true everywhere, it's a convention not a hard rule. If Wikipedia were friendlier they'd do a redirect there instead of 404-ing.

There's a reason:

http://en.wikipedia.org/wiki//

http://en.wikipedia.org/wiki///