This update should be related to 'Unnatural link" notification that many webmasters received previously and supposedly would help to eliminate those 'unnatural links'
Per Ad Dale only people who would find this tool useful (or would try to use it in the first place) are 2 kind of people: Desperate Webmasters hoping to get their ranking back (And it probably would not work) and "Negative SEO" specialists who would try to tank their competitor's websites.
Check the link if you are curious... It is pretty interesting.
Beware Google Bearing Gifts… | Ed Dale's Blog
We are probably going to get many new "The Skies are falling again" messages and posts coming.
Another interesting article I found about Negative SEO and how Google finally is ready to admit that it exists.
Google confirms “Negative SEO” | SEO Melbourne | Appear On The First Page Of Google
My take on it... I would be careful to trust Google with new update. They maybe mean good and what they are doing could be good for them, but not for regular webmaster. We are probably would see interesting new wave of Negative SEO attempts and "SEO recovery projects/ job request" coming