Of course, this breaks applications right and left. Any application that distinguishes between "no such domain" and "server not responding" or "connection refused" errors will do the wrong thing if it queries one of Earthlink's servers. They're very different kinds of errors — "no such domain" is a user error or application configuration error while "not responding" or "connection refused" is usually a temporary problem with a server or the network. Many applications will report the first condition as an error immediately while treating the latter as a temporary error and retry the connection, or try to connect to a different server before giving up.
But it's even worse than that — if the host you are trying to reach has only IPv6 addresses and your application queries for IPv4 addresses first, it will get the bogus IPv4 addresses of completely different hosts than the one you are trying to reach, and might never even see the IPv6 addresses that are assigned to the host.
for other discussion on this, see http://www.gossamer-threads.com/lists/nanog/users