Well it looks like there was some sort of an update recently in Google-land. According to a quick snapshot by Dr. Peter J. Meyers, it looks like the number of search results receiving knowledge graph results has greatly increased recently.
This is a fantastic bit of news for savvy developers/producers, as essentially a few bits of code can really help a piece of content to ride this wave.
This is a sign! This is a sign that Google is now more closely heeding your references and markup and accordance to structured data such as Schema.org. Take every chance you can to [properly, and without spam!] markup your content, and to those selling: your product content is a huge opportunity here! Markup your content so that Google is able to recognize your products as products!