Gmail Labs新推出了一项功能Sender time zone ，可以方便地查看发信人所在时区时间，在Gmail Labs中打开它，然后在邮件中点击show details就可以看见发信人所在时区时间了。绿色电话表示方便沟通，显示红色电话时表示发信人应该在睡觉或者离开。猜想应该通过邮件头中的Date域来判别的。
然而，我们在Googel Reader（等等）里用email分享文章时候，在邮件头中显示的并不是发信人的时区，而是Googel Reader外发邮件服务器的，这就产生了误判，你可以在Google reader里给自己发封邮件重现之。看下上面这份帖子的邮件头：
Received: by 10.100.108.16 with SMTP id g16cs62702anc;
Wed, 8 Apr 2009 20:55:35 -0700 (PDT)Received: from mr.google.com ([10.229.105.20])
by 10.229.105.20 with SMTP id r20mr1763231qco.8.1239249335573 (num_hops = 1);
Wed, 08 Apr 2009 20:55:35 -0700 (PDT)Received: by 10.229.105.20 with SMTP id r20mr255572qco.8.1239249327216;
Wed, 08 Apr 2009 20:55:27 -0700 (PDT)Received: by 10.177.2.5 with SMTP id e5gr101415yqi.0;
Wed, 08 Apr 2009 20:55:26 -0700 (PDT)X-Sender: 3rXHdSQsJBEYuqiw.ozipiuouiqt.kwuniv0owwotmozw2×0.kwu@feedreader.bounces.google.com
X-Apparently-To: fans@googlegroups.com
Received: by 10.90.95.18 with SMTP id s18mr1256989agb.28.1239249325843; Wed, 08 Apr 2009 20:55:25 -0700 (PDT)
Return-Path: <3rXHdSQsJBEYuqiw.ozipiuouiqt.kwuniv0owwotmozw2×0.kwu@feedreader.bounces.google.com>
Received: from mail-gx0-f229.google.com (mail-gx0-f229.google.com [209.85.217.229]) by gmr-mx.google.com with ESMTP id 39si525226yxd.9.2009.04.08.20.55.25; Wed, 08 Apr 2009 20:55:25 -0700 (PDT)
Received: by gxk13e070377e with SMTP id 13so1330943gxk.2 for <fans@googlegroups.com>; Wed, 08 Apr 2009 20:55:25 -0700 (PDT)
Received: by 10.150.49.15 with SMTP id w15mr1283942ybw.22.1239249325751; Wed, 08 Apr 2009 20:55:25 -0700 (PDT)
Date: Thu, 09 Apr 2009 03:55:25 +0000
可以看到邮件是从209.85.217.229发出的，用ip工具可以看到该ip确实是在-0700，而不是+0000。但是奇怪Date域为什么不设置为-0700 (PDT)，而是+0000。
建议：如果Google Reader能根据我的ip在发信时候自动将Date域转换成我的时区就NB了。