Cyrus Shepard posted on Google+ about a case study he posted on his blog about the results after he disavowed 35,000 links pointing to a site.
He said, "On April 3, 2013 I disavowed every link to my website I could find through Google Webmaster Tools." That turned out to be 35,000 links. The result in his traffic? Well, hard to say.
Here is the chart:
He said, "shortly after" he disavowed all those links, "Google released Penguin 2.0 in late May, my rankings started to drop." They dropped like a rock," he added.
Was it Penguin 2.0 that caused the drop or disavowing all the links Google knew about and thus removing all the PageRank and trust Google flowed to his site?
The only way to tell is to wait for another Penguin refresh.
The thing is, disavowing all your links that Webmaster Tools returns doesn't mean you've disavowed ALL your links. Google doesn't show all your links in webmaster tools. That being said, others have tried to disavow all their links and Google has come back to them to tell them there are still links that are pointing to them that are bad. This is why Google says use the tool with caution but like a machete.
In this case, I am not sure if these two things are 100% related.
Forum discussion at Google+.
This post was written earlier this week and scheduled to be posted today.