fred9989 - 9:18 am on Mar 3, 2012 (gmt 0)
Having looked through my portfolio of websites this afternoon, I see some changes in ranking that look significant....exactly how or why they are significant is harder to analyze.
I cannot find any simple explanation for these changes, though the websites cover several fields, so that may not be unexpected just because of different factors being applied differently to different areas of search....
My intuition says:
Medical type sites: the site authority factor required for good ranking has been increased again to exclude "amateur" sites or those with a sales pitch.
Travel sites: I sense there has been some adjustment to the on-page keyword density or link anchor text keyword density factors. I find it hard to believe, but it looks like the on-page keyword density now needs to be higher on one of my sites.
But as always, things are unclear. In a chaotic algorithm with so many factors, how could it be otherwise?