I have been trying to figure why my site has dropped from top 30 to 400 and stayed there for last 4-7 weeks for major keyword in serps. Can any of you list some good reasons why this would happen and what can be done to correct it.
Changes recently: Moved sister site - www.celebrationcandy.com to same server/host and now looks similar and does have one section of same products, but different focus and copy has been altered etc. They are not mirror or gateway sites. Other than that, I continue to tweak copy, add pages, post on my blogs and others, write articles and enter sites in directory submissions. Fluctuation of this magnitude seems like penalty, but I cannot figure out the reason other than moving second site. And, only seems to be affecting 2 key phrases (promotional products, promotional items) - long tails not affected.
I've seen sudden SERPs drop on a couple of sites that have received a sudden and uncharacteristic surge in backlinks (though legitimately acquired). My advice is go right back to SEO basics and double check you are not doing anything that is likely to raise suspicion. In particular, over-optimisation seems to have become a more significant issue in my experience.