Some sites obviously should be ranked lower than others. For example, there are websites than completely copy popular blogs like Engadget, but put ads on the side which they get the money for. I personally had this experience with one of my blog posts being copied onto another blog. Websites like this are called content farms.
With other sites, it's not so clear where they should go in the search results. Some websites are completely legit, but many users would not deem them useful, and therefore do not want them in their search results. Such sites include eHow.
eHow is a website with many how-to questions and answers. People in the technology business do not seem to like eHow, and think that the content there is not useful. I personally have used eHow and like it. Some of the content may seem simple, but a lot of it is useful information. Before this algorithm change, a search for any how-to question would usually bring an eHow article at the top. Now a search brings in eHow and sites like it after more legit looking sites. Interestingly, the eHow website has a link to a survey.
The eHow survey asked quite a few questions, all of them having to do with whether or not eHow is useful. This seems interesting, and with the recent algorithm change, I wouldn't be surprised if eHow takes the survey results to Google, saying that the results show that internet users believe that eHow is useful, and that it should rank higher in the search results.
The obvious response of Google should be that the users surveyed were eHow users, meaning that the general internet does not necessarily think of eHow as useful, and still doesn't wan't it clogging up the search results.