The latest video of Matt Cutts puts all the SEO misconception regarding the Google ranking and search quality patent into rest. Cutts, who takes care of the search spam at Google said, just because Google has ranking or search quality patent doesn't mean that it was or is a part of our algorithm.
Referring to the Ranking documents patent, Matt explained that Ranking documents is one of the patents that Google holds and is currently not built in the ranking algorithm. He further added that, having a patent doesn't mean that Google is necessarily using that patent. Matt pointed out that SEOs and webmasters act on these patents and at times give up on their websites just because of the patents.
The whole point of Matt Cutts coming up with the video was to convey that just because Google has a patent or a patent application; it doesn't mean that Google will be integrating it in the algorithms.
Have a look at the Video:Having a Patent Doesn't Imply That Google is using it in Search Quality; says Matt Cutts!,