A copy of the email is below. My only issue with this is, I do not own that site. I do not see my adsense code there on the site either. I was online when it came through and I viewed source on the site to see if they used it. My earnings were no higher the past while then normal and have not dropped any. That site is huge. I cannot see them using my code anyway. Makes no sense... Anyone make sense of this? I don't even see links to my site on the page they listed as an example.
I got the same - only the reason was a choice of 7 or 8 - none of them really valid either... Adult content wasn't available on the forum, so I thought that would have been ok.
Use Google Webmaster tools to see if your links or codes are used in any other site. Fill an appeal form in Google adsense page and explain them the issue
To avoid this now and in the future, use the "Sites Authorized to Show Ads" option in your Account Settings so that only your site/sites is/are able to display and accrue earnings.