Hello Daniel White,

While going through our records recently, we found that your AdSense
account has posed a significant risk to our AdWords advertisers. Since
keeping your account in our publisher network may financially damage
our advertisers in the future, we've decided to disable your account.

Please understand that we consider this a necessary step to protect the
interests of both our advertisers and our other AdSense publishers. We
realize the inconvenience this may cause you, and we thank you in
advance for your understanding and cooperation.

If you have any questions about your account or the actions we've
taken, please do not reply to this email. You can find more information
by visiting
https://www.google.com/adsense/support/bin/answer.py?answer=57153&hl=en_US.

Sincerely,

The Google AdSense Team
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Adsense is an ultra-sensitive program no doubt.  You r e a l l y have to make sure you cross your I's and dot your T's.  And even then you still really never know!  Do you see any cause for this letter from Google or do you have no idea why they sent it to you??

I've heard this many times in the past and it's really sad how much control Google has on small online publishers.   I recently started paying with rubicon project just incase I ever get this email... 

www.rubiconproject.com

essentially they load you up in their ad server and mix and match ad products.  They take 1 or 2% of the take - which isn't bad for the risk they take.