Why don’t some websites work without the www. in the beginning? I thought that was a thing of the past…
ANSWER PERSON RESPONDS: Their servers are only registered with the www prefix or aren’t configured to redirect from the non-www to the www form of the name. Most major government websites, for instance, will work with or without the www (try the Library of Congress at either loc.gov or www.loc.gov). But some, however, only work one way (www.census.gov works, but census.gov doesn’t).
So, it’s still up to the site administrators which address will work, or both. It depends on the server configuration.
Some of this is touched on at http://en.wikipedia.org/wiki/No-www and at http://no-www.org (although there is very, very little at this site).