Let's see what happens when we add an extra letter to some popular web addresses.
You'd think they'd all be trying to ride on the fiber optic coattails of their more popular brethren. You may be correct in many cases.* Here are a few exceptions.**

It's an archive of the FAQ from the Usenet group alt.magic, a group for magicians to discuss their craft. The most recent updates to the FAQ are from 1998 and they're mostly listings of brick-and-mortar magic equipment suppliers. I wonder how many of them are still in business.

A choice quote from one of the supplier descriptions: "He uses a tremendous amount of hyperbola in his advertising..." Are these people magicians or mathematicians?

An Amsterdam-based web design studio. They seem like they made a good choice.

Redirects to a site for some manner of art-printing business. The images are largely uncredited, leading me to suspect they were hijacked from Flickr. They also offer a sizable collection of Licensed Artwork From Star Wars, so if you're still looking for that finishing addition to your Boba Fett-themed living room, try Amazon because there isn't a retail frontend on this site.

*Most single-letter modifications to google.com appear to lead straight to Redirect City by way of the Download This Surreptitious Software Bypass.

**atwitter.com is for sale!