slawski - 1:53 am on Aug 19, 2012 (gmt 0)
The Google patent Information retrieval based on historical data [appft.uspto.gov] did mention something somewhat similar. That got picked apart by a lot of people back when it was published as a pending application back on March 31, 2006.
In addition, or alternatively, search engine 125 may monitor the ranks of documents over time to detect sudden spikes in the ranks of the documents. A spike may indicate either a topical phenomenon (e.g., a hot topic) or an attempt to spam search engine 125 by, for example, trading or purchasing links. Search engine 125 may take measures to prevent spam attempts by, for example, employing hysteresis to allow a rank to grow at a certain rate. In another implementation, the rank for a given document may be allowed a certain maximum threshold of growth over a predefined window of time. As a further measure to differentiate a document related to a topical phenomenon from a spam document, search engine 125 may consider mentions of the document in news articles, discussion groups, etc. on the theory that spam documents will not be mentioned, for example, in the news. Any or a combination of these techniques may be used to curtail spamming attempts.
That was a pretty good hint that Google would monitor changes on pages and in links to those pages when those changes might result in significant changes in rankings. That Google would continue to monitor changes if pages didn't actually rank as well as expected in response to those changes, or even possibly lose rankings, to see what a site owner might do next also made a lot of sense.
This new patent provides a framework for that kind of monitoring, and some vocabulary that could be used to describe it.
Many of the other patents that were filed as continuation patents from the Historical Data patent discuss a lot of other places where Google is monitoring changes to anchor text, to content changes, to frequency of links pointed to pages, and many others.
I have seen the kind of delay that's likely associated with this, followed by a rise in rankings (no hidden text, keyword stuffing, misleading redirects, or unnatural links involved). What's troubling about this is does appear very much to be a fishing expedition.