Previously, I commented about the difference in the MSFT and GOOG ecosystem. Thousands of companies support and enhance the Windows OS, and over at GOOG, thousands of companies try to break their foundation (SEO).
Domain Parking, where folk own domains with wonderful traffic, due to search engine optimization and wonderful names (chocolate.com comes to mind), primarily earn revenue, not by adding incremental value, but by referring this traffic to other sites; effectively exploiting a search loophole that adds clicks between users and their desired destination. Therefore, you can think of Parking, in part, as a bane of search engines with a continued cat and mouse battle between the sites and the engines. As you would expect, many of these sites are often masters at SEO to maximize rankings to capture first time surfers.
The other day, Google announced Adsense for Domains, to assist the parkers with maximizing their revenues. Historically, Yahoo has been the largest supporter of Parkers, who often go directly to parking aggregators such as Sedo, GoDaddyand DomainSpa.
It seems as if the contraction of GOOG's growth has them 'shining the light in the darkest of places'.