jadebox - 6:43 pm on Oct 31, 2012 (gmt 0)
I think I got hit by that. I have a site with a domain name matching the first and last name of the person the site is about. It's very much a niche site because the subject is someone that most wouldn't recognize by name. On September 28 or 29, traffic from Google dropped to less than 1/4 what it was.
The site has thousands of inbound links - all generated naturally as people linked discussions or articles about the person to my site. Probably 99% of the inbound links use the exact person/domain name as the link text.
Replying to myself ... and hoping it might provide a clue to all about what happened ....
Looking at stats from WMT and Analytics, it looks like that, since the 9/29 update, Google has been matching my EMD site less to queries about the person the site is about and more to queries related to one of his works.
Keywords directly related to the person's name and pimary reason for fame are sending about 70 to 80% less traffic. Keywords related to the title of the one specific work of his are up significantly - some much more than 100% over last month. Unfortunately the title has a sexual connotation and the keywords sending more traffic are related to that connotation.
It appears that Google has totally lost track of what the web site is really about.