I've been banging my head trying to solve a mystery for a few months, with little luck. Maybe one of you has an answer.
My home page organic SERP rankings have dropped from #1 or #2 late last year, to between #8 and #25 a few months ago for a couple of important keywords.
I did not make any on-page changes during this period.
Meanwhile, many inner pages continue to rank well (top 5) for long-tail keywords.
All of my SEO is white hat, no unusual on-page tactics, no purchased or otherwise fishy backlinks. In fact, looking closely at the on-page and backlink tactics of some of the websites that have leapfrogged ahead of me, I'd say some of them have (and continue to) engaged in shady practices.
No errors reported by SEOmoz. I've been judiciously applying canonical tags and other techniques to ensure minimal duplicate content.
I've not received a letter from Google warning me of any unnatural backlink profiles.
The biggest part of the mystery is that it seems like my home page was the only page really affected. As mentioned above, the inner pages continue to rank well for their respective keywords. Thus, I don't think I've been hit by any kind of site-wide penalty.
Also, I continue to rank well on Bing/Yahoo.
Does anybody have an insight into what could have happened? Has anybody else experienced anything similar (home page dropping rank while other pages stay put)?