How Google Is Cleaning The Web Of Comment Spam
forbes.com
forbes.com
A blackhat actor puts links to your site all over their network of bad content sites and then forces you to pay them to remove their link.
A competitor might create bad links to your site to push you down in Google's SERP and you'd never know what was going on if you didn't know how to look this up.
A "disavowal tool" was meant to help combat this kind of extortion, but imagine how much work it would be to monitor this kind of activity and disavow all sites that might want to create bad links to your site to drive you down.
As mentioned in other comments, the changes described may just change the spam. Instead of linking to your own site, you instead link to sites ranked above yours.
But here is the thing, Google has a content evaluator as part of their Adsense for Content product and they should be able to compute the equivalent of the 'hamming distance' between the linked pages and the content on the current page and construct a decent rank. Certainly that is what I would do if I had the resources to crawl as much of the web as they do.
Hate giving people ideas, but a majority of the fiverr SEO services are geared towards spam/link bombing competitors.
Maybe that's not the intended use of the "SEO" services, but I fail to see what else they would be good at.
http://www.forbes.com/sites/kellyclay/2013/11/19/seo-isnt-de...
The spammers have more tricks than they used to, and aren't telling most of the SEO's how to game the system, but Spam is actually easier because Google is weeding out the people who don't have the time or ability to do Page Construction spam.
I've run a small wiki for many years. I'm probably going to shutter it because it's such a target for link spammers. (MediaWiki's anti-spam tools aren't very good unless you have many dedicated editors.)
Now that a critical mass of people are using Chrome, I suspect that there is a much better signal in the haystack of user behavior data than back links. A much better algorithm in theory could be built using the actual usage patterns of discriminating humans rather than the link landscape of the web.
I would far rather the google data be made public
It doesn't tell you anything about it, the post author wasn't notified either.
The best solution is removing the incentive (though I've had rel="nofollow" auto-added to all links since it was first proposed, to no avail...).
Google has a $50 billion annual revenue inventive from advertisers to not give a shit about our privacy. There's very little incentive to protect user privacy because people are easily tricked into believing that trading their privacy gets them something free in return when in fact it is not free at all, and in fact even more expensive than it would have been [1].
What is needed is a non-profit, open-source search engine. And the same for social networking. Perhaps Wikipedia style. Let's ditch the bad incentives.
[1] No free lunch, no free web, https://news.ycombinator.com/item?id=6624666