Here, techcrunch was complaining about Google's newly released feature of being able to change the ordering of the search results. The point that seemed to have escaped people is that, the search results that you change are only local to you. Other people don't see them.
Because of that, I think Google can encourage the behavior where people are sending links relevant to themselves up to the their front page in an honest way. If they click things up that have no relevance to themselves, they only screw up their own searches.
So if you have millions of people sending things relevant to themselves up the list, Google is basically gathering data about what the human 'gold standard' for a particular search query is (augmented by machine sorting first).
In information retrieval, one of the hard things is to know whether you've done a better job of returning search results or not, since a gold standard dataset is hard to come by and time consuming to produce.
Here, I think Google is simply using a mechanism where they're aligning people's self-interest to create accurate data they can use to compare their search algorithm tweaks.
All in all, a good thing. Even better if you can 'merge' search results from others that you trust..say your friends. I wouldn't mind merging my search results with _why's. More complexity that way, though.