@SevenCubed, they do big time. Dupes , crap links, massive amounts of ads and thin pages. They have been there for the longest I remember too. This is the 1st positive tweak(not comparing to me gaining ranks, just in general) for those selected serps in the spawn of at least 2 years.
Now if they can really fix the domain crowding and the crap news/info articles sites populating wrong verticals it would be almost shinnnyyyy.