in my one competitive keywords, i was on 11. position one month ago.suddenly it went down to 6th and 7th page and sometimes 5th, dancing for 1 month.I have read some advices in the forum to keep on building links and i did it.I built some more links for that keyword to my main index page.And now I have went down to 12th page(6-7 more pages back). Could it be a penalty like -60? and when i keep on building links , one more -60 penalty? or could it be something different? By the way I am not sandboxed. My indexes are still shown when i search site:mysite.com on google. And if it is a penalty how long will it take ? what should i do ? Thanks in advance.