Google is really stepping up their transparency about sites spamming them.
A Google Webmaster Help thread has a site owner upset his site no longer ranks for [maternity jeans] in Google.
Google's John Mueller came in and responded that the reason is they have been link spamming the site to try to rank for that term. John even added there is someone out there leaving blog spam on sites pointing keyword rich links to your site.
John said, there is "blog comments left by someone called "Maternity Jeans."
Here is John's full response:
It looks like your SEO (or previous SEO) may have tried to promote your site in a way that's in violation of our Webmaster Guidelines. Specifically, I see a lot of unnatural links in low-quality articles as well as blog comments left by someone called "Maternity Jeans." Stopping these practices, cleaning up unnatural links like these, and using the disavow links tool in cases where you can't clean them up, would be a good step in the right direction. Over time (and this process can take months), as our algorithms recrawl the affected URLs, reprocess the links found on the web, and update their data, they'll be able to take the new state into account.
So now the site owner goes through the link removal/disavow process.
Forum discussion at Google Webmaster Help.