I stumbled onto this while verifying that my redirects are working as they should.

$ wget -S http://blog.foolip.org/
[snip]
HTTP request sent, awaiting response...
  HTTP/1.1 200 OK
  Server: nginx
  Date: Fri, 16 May 2008 22:40:05 GMT
  Content-Type: text/html; charset=UTF-8
  Connection: close
  Vary: Cookie
  X-hacker: If you're reading this, you should visit automattic.com/jobs and apply to join the fun, mention this header.
  X-Pingback: http://blog.foolip.org/xmlrpc.php

I’ve already renewed my contract with Opera for the summer and beyond, but I though it was pretty neat. However, I am not the first to discover this little easter egg...