Google is 302 redirecting anything with a WinPhone user agent to the main page. This may be a bug rather than an intentional thing, but it's Google's bug to be sure." Source: http://www.reddit.com/r/technology/comments/15yx0a/after_mic...
[1] http://i.imgur.com/Hfum6.jpg
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And update here:
http://www.theverge.com/2013/1/4/3836510/windows-phone-8-use...
Seems this is 100% intentional from Google. What the fuck? I was completely blindsided by this, I couldn't imagine a huge company like Google doing this at this scale.