I would say it continues to worsen in my areas at a considerable pace. Google seems to have squashed one type of spam and it was replaced, that quickly, with what you mentioned in that patent regarding targeting keywords. Reno described it to a degree, a month ago, as to what the site of the future would be.
I've looked at over 100 of these sites, in depth, and they're just info sites ranking from a grammatical standpoint with no real substance. There would be no good reason to revisit the sites. To me this is the new spam showing the flaws in the filters. It definitely pushes small commerce down because the only thing that could beat these keyword targeted sites out is a boatload of links. How do you compete against sites that are written specifically just to comply with a filter but have no real quality except as determined by an automated algo?