I have a 2 month old niche blog which was ranking in the first page in all three major search engines for the main keywords. All my link building was whitehat using manual social bookmarking and blog commenting. Suddenly I see that my rankings in Google were pushed down by roughly 80 positions for all the relevant keywords. I am experiencing this kind of penalty for the first time. When I checked at my link profile, I could see an inflation of incoming links because of too many sitewide links from the blogs I commented on. Has anyone else experienced this Google minus 80 penalty? PS: I have adsense on my blog.