Who knows, but results change all the time - they are not static.
Actually I've heard all the engines have algorithms that give you the results you want to see, and that includes political points of view. Like depending on your history the results for search on Obama would be very, very different. It's not so much filtering, as prioritizing. Maybe that has something to do with it.
I bet if you find the story on Adkins, follow the links, then go back and search again, multiple versions of the story will be on top of the list of results. Or for that matter, if you followed some FR links it might do the same thing. Now that would be an interesting experiment.
Maybe the fact you did not get the story on Adkins in your results indicates that you spend most of your time on left wing sites!! (Just kidding.)