Not sure if its Panda but on couple of our sites (keyword names) i.e. bluewidgets.com dropped for main keyword"blue widgets" in google.com after many years of being in the top 2. Now we are 4th and the other site 5th. Hopefully its a glitch and things change for the better. This has happened to 2 sites of ours but the rest is untouched and normal as last Monday.