Oh yes I have been hammered, I got hit last year from a 4 to a 3 and found the dodgy link.
On Thursday I was feeling all smug that my newly designed site had a 100% organic traffic tranaction rate, I was very puzzled to have no orders at all over the weekend (I sell jewellery and it is December)
I had a look in webmaster tools and placed an order from my phone and the site, then I saw the toolbar and nearly had a canary
I have never bought backlinks, only have high pr niche directories, no black hat, I follow all the rules and BAM!
I am now afraid to post on forums in case there is a link I have not found that is causing me grief so from now on I am incognito and changing my name from Silverbling to Itsasecret.ie!
Edited because I can not spell transaction