tedster - 6:25 pm on Jun 19, 2011 (gmt 0)
I'd say that NATURAL semantic variation in anchor text is what's in play, and what got tuned up big time. Statistical measurement of what's "natural" has long been a major part of what Google does. If they tune-up their semantic processing, then that has major implications in many areas of the algorithm.
Here's a thread from 2006 that applies even more today: Natural vs. Un-natural - in SEO and the Google Algorithm [webmasterworld.com]