c41lum - 4:16 pm on Jul 27, 2010 (gmt 0)
I think that it has caused us a "quality" drop in Googles eyes not a all out penalty like what you see from duplicate content. We haven't jumped back -50 we have gently slid from page 1 to page 2 and in some cases to page 3. This happened over a 6 month period.
Maybe a case of as G found more and more 404's it pushed us further back down the SERPS.
Anybody else had a similar problem?