tedster - 3:18 am on Oct 9, 2012 (gmt 0) [edited by: tedster at 5:06 am (utc) on Oct 9, 2012]
The first time anyone noticed a site that previously had a top ranking demoted to position "-950" (in reality just somewhere near the end of the results) it was what turned out to be an over-optimization penalty. In this case, the same demotion seems to be happening, but the cause is more complex.
Here's a summary for the historical -950 penalty [webmasterworld.com]
[edited by: tedster at 5:06 am (utc) on Oct 9, 2012]