See

http://googlenewsblog.blogspot.com/2011/04/automatic-personalization-and.html

<< ....Starting today [21st Apr] – if you’re logged in – you may also find stories based on articles you’ve clicked on before.
For signed-in users in the Personalized U.S. Edition, “News for You” will now include
   stories based on your news-related web
   history. >>