I experienced a +100 penalty for a couple of keywords earlier this year. Went from position 1 to page 10 overnight. Pretty sure it was due to building too many links with the same anchor text. After removing them / altering the anchor texts they slowly crept back. Still not regained the no.1 spot.
Guess who got his positions back Anyway,i guess reason of penalization was toomuch missing internal pages,and funny thing is i started building internal pages yesterday after i paused after first rebuilding when penalization started.I guess new content triggered this Also seo penalty site now shows 0 score which means that site shows correctly if someone penalized or not.Also now that same keyword have competition of 599,000,000sites while before was only 88,000,000 sites.
well buddy i think you should now focus on Link trading. referring and so. As Once google penalizes, its hard to get out of the mess it makes. You may find out what is the problem, remove the problem. Then write some letter to google. If lucky, you may be back. try that.