Got this email from Google: I can't see anything wrong with my site, nor find any hidden text on it. Though the adsense on the site have been showing drug ads, which is very strange. Any ideas what is going on?
Maybe google made a mistake? If you do not have any hidden text on your site you should write them back and let them know.
That usually means your site has been hacked, probably with a bot , the intention to search engine spam, if you want post your site , this is quite common at the moment. http://www.mattcutts.com/blog/helping-hacked-sites/
That usually your site has been hacked, the intention to search engine spam, its may be a different crawler... try google webmaster tools than you will get perfact result