Google seems to be testing a new feature where you can hover your mouse cursor over a link in the search results by the URL of the snippet, and it will overlay a text preview and summary of the search result. The preview may just explain what the name is about, and it may not even pull from the page linked to in the snippet itself.
For example, from @tecnonetblog, you will see a search for [the walking dead] returns a search result from amctv.com and if you hover over the link preview, it shows an overview of the channel from Wikipedia.
Here is a picture, click on it to see the full size:
I am not sure what Google calls this test but it is clear that it provides somewhat knowledge graph like information about the search result.
Forum discussion at Twitter.
