MikeNoLastName - 8:53 pm on Oct 14, 2006 (gmt 0)
If you call this the -30 penalty, then you'd have to call the duplicate content penalty, the -100 penalty. Seriously. About a year ago when we had problems on one domain with the www/non-www canonical issue and a lot of pages started showing up twice, our top pages all dropped to exactly their former positions -100. Once it was fixed they returned to the +100 state. I also am convinced there is perhaps a -10 penalty that I've observed which seems to have something to do with too high keyword density.