M_Bison - 12:16 pm on Oct 14, 2006 (gmt 0)

I think I was subject to this "minus 30" penalty a couple of weeks ago.

My site is 8 years old.

Basically I did implemented mod_rewrite, which then meant googlebot crawled thousands (eg 5000 per day) of pages, mostly duplicate content.

About ten days later I noticed the drop in ranking for a 1 word search term of about 30 spots - ~30 to ~60. Other search terms weren't really affected.

I then excluded those pages via robots.txt.

Haven't really moved up in the rankings, maybe 1 or 2 spots since then, but have learnt my lesson and am currently working to produce good, quality content on my site, not duplicate rubbish.