There is a lot of noise in those threads, but you can put some pieces together from them. One of the best comments is from Joe Sinkwitz:
1. Phrase-based penalties & URL-based penalties; I’m seeing both. 2. On phrase-based penalties, I can look at the allinanchor: for the that KW phrase, find several *.blogspot.com sites, run a copyscape on the site with the phrase-based penalty, and will see these same *.blogspot.com sites listed…scraping my and some of my competitors’ content. 3. On URL-based penalties allinanchor: is useless because it seems to practically dump the entire site down to the dregs of the SERPs. Copyscape will still show a large amount of *.blogspot.com scraping though.
Google, URL, Keyword, Google Filters, Penalties