Twitter now wraps all links passing through the service with the t.co link shortener, which I wondered about a little while ago. Twitter engineers sweat the details, even the HTTP response headers are concise:
$ curl --head http://t.co/WXZtRHC HTTP/1.1 301 Moved Permanently Date: Sun, 21 Aug 2011 12:17:43 GMT Server: hi Location: http://codingrelic.geekhold.com/2011/07/tweetalytics.html Cache-Control: private,max-age=300 Expires: Sun, 21 Aug 2011 12:22:43 GMT Connection: close Content-Type: text/html; charset=UTF-8
Oh, hi. Um, how are you?