onepointone - 6:54 am on Feb 4, 2012 (gmt 0)
These internet mega-companies strive to get businesses to post their important and newsworthy content on the mega companies properties. Google places, google shopping, etc.
Facebook and Twitter the same way.
Deteriorating SERPS mean, these internet monoliths gain in relation to the original websites. The original websites lose in relevance and importance. These businesses are handing over their power to control their business to a degree.