So over the past few months it seems like Google has made an effort to include at least one answer service result for a lot of the search queries, and now it seems as if they are cycling the results. If you do a Google search you will most likely see one or two questions from answer sites like Yahoo! Answers, QnA, Lyqos IQ, Fluther, Answerbag, Wiki Answers or wikihow, or Askville come up.
Surprisingly enough, if you do that same search 24 hours later, you will likely get a different result and different answer services. Of course this depends on how competitive the keywords you’re searching for are and if people are actually asking questions relative to your search, but it seems as if Google has predetermined that at least one of the results for every search should be from an answer service, and to cycle them daily.