A few days ago I changed my preferred domain in WMT from "Don't set a preferred domain" to the www version. I just wanted to be sure all my backlinks where being picked up (from the non www version of my address). An hour after i'd done this my main keyword dropped 20 places. The next day all my keywords had dropped. Today some are ranking in around 80th but for the wrong pages. So the keyword "blue widgets" is showing my page on "dark blue widgets". Has anyone had this happen to them? I'm pretty confused as to why this would happen :s Do I just need to wait it out? I don't think it was to do with the new panda update, my site danced a little from that but nothing like this.