Sgt_Kickaxe - 2:59 pm on Oct 28, 2011 (gmt 0)
Anyway...to cut a long story short, I am confused!
Keeping webmasters in that state of mind is a profitable endeavor for Google.
Have you been posting new content during the free fall? If so perhaps your best content is getting buried in your navigational system and/or your sites average article age is falling quickly (might be one of 200 ranking factors, only Google knows).