Edit: the 1000s figure is not an exaggeration. Go to fiverr and search on "back link" to see.
- Download your links from webmaster tools.
- Edit the file so it contains just the undesirable links.
- Use the disavow tool [1] to upload the file. (If your livelihood depends a lot on organic traffic, that is one scary red button. The wording on the page coupled with the button text makes it sound like you will disavow all the links to your website.)
[0] http://support.google.com/webmasters/bin/answer.py?hl=en&...
[1] https://www.google.com/webmasters/tools/disavow-links-main?p...
"- Edit the file so it contains just the undesirable links."
That's the part where intensive manual labor comes in, weeding through those links one by one.
I also noticed that the help page states "(the file type must be .txt and it must be encoded in UTF-8 or 7-bit ASCII)". How many non-technical people even know what that means?
And what are the chances that if somebody doesn't know what that means they will mess it up? It is not like UTF-8/ASCII is something that you have to go out of your way to choose.. it is going to be what is defaulted to.
So:
company pays crap SEO to place spam links all over the globe to increase google rank
google increases page rank
crap SEO works a bit more together with 1000's of fellow crap SEOs
google increases page rank
google notices problem, starts penalizing sites with crap ranks
companies that previously employed crap SEO to spam now pay crap SEO to blackmail site owners previously used to place spam links on to remove links 'or else'.
Really, this is not a good development. The burden of dealing with spam is bad enough, now we need to deal with being blackmailed by SEO spammers to clean up after them as well or risk being penalized in google? wtf?