Continuing with analysis of Google’s recent (February 2012) search quality updates, now referred to as Google Panda 3.3:
More accurate detection of official pages. [launch codename “WRE”] We’ve made an adjustment to how we detect official pages to make more accurate identifications. The result is that many pages that were previously misidentified as official will no longer be.
Google (or at least their CEO, Eric Schmidt) sees Brands as the way to sort out the cesspool that is the internet. So making sure that the official pages, especially of big brands, are properly identified, should be a priority of Google’s search algorithm.
As this seo blogger points out, the change is probably aimed at sites that attempt to identify themselves as official pages, but aren’t, thus taking advantage of that boost in ranking that Google gives to official pages. If your site attempts this, your ranking may have been hurt, and rightfully so. Most SMBs (small or medium sized businesses) were probably unaffected by this particular tweak.