My main site got hit by the penguin update all of the keywords were out of the top 300 or totally deindexed. How I have got some of my keywords back in the top 10 I even got 1 keyword to 2 for a medium competition keyword it was only 8 for that keyword before the update. What happened was after the update I decided to to try and get traffic from other places not just Google so I made all of my new links aimed 100% at people clicking them not at Google at all and did a lot of tweets and retweets around 4k in total I think no spun content at all and a lot of social bookmarks I made a 50 to 100 word description on the bookmarks my self a lot of posts on stumblupon, digg and reddit got me a lot of traffic and also helped with ranks. I also added 40 Google +1s to the landing page and 1 to 10 on some other pages. I made about 200 links on Facebook just pages that are related to my site in some way not really trying to get people to click the links I tried to make the comments about there page and get a link to my site in there in some way but make the comment good so they don't remove it and made a Facebook fanpage for my main site and got some fake likes that helped me get some real likes. I also added links to about 50 link directory's they was also aiming at clicks not for Google all descriptions was made by me unique on every post only about 40% of the links pointed to my landing page all others where to other pages on the site. I think any social signals are helping a lot also I like them because they give you traffic as well. I hope this helps.