This question already has an answer here:
A few months ago I received the following notification on Google Webmaster for a website I look after.
Unnatural links to your site—impacts links Google has detected a pattern of unnatural artificial, deceptive, or manipulative links pointing to pages on this site. Some links may be outside of the webmaster’s control, so for this incident we are taking targeted action on the unnatural links instead of on the site’s ranking as a whole. Learn more.
The question here is, should we actively attempt to disavow these links given that the action is seemingly targeted to just a bunch of keywords? I've downloaded the inbound links sample from Google Webmaster and so far I've been through the disavow and reconsideration requests process 6 times, each taking 2-3 weeks only to be supplied just 2 more links that Google don't approve of. At this rate it will take me the rest of my natural life to cleanup all these spammy links!
It seems disavowing is futile as they haven't implemented broad actions against the website as a whole and (from what I can gather) have already nullified the value of those offending links. Under the quoted statement above however is a reconsideration request button that seems to imply I should be actively doing something here?
UPDATE 14th October --
I have since created a small .NET application that you can feed the CSV sample links file into from Google Webmaster. What this tool does is crawl all the links and looks for specific linking patterns as per some configurable match strings.
I realised that many of the links that Google are taking issue with were created by a rogue SEO firm we hired several years ago. All the links are appended with 1 of 5 different descriptions. The application I built uses some regexes to isolate any link sources with these matching appendages and automatically builds the disavow txt file.
In the end it had to come down to an algorithm as manually disavowing links on this scale would take weeks!
I will post the app here once I've cleaned it up.