抄録
In my two previous reports based upon a survey and analysis of search results of Google and Yahoo!JAPAN, I demonstrated that the latter search engine is more suitable for the purpose of searching for Japanese phrases and getting a grasp of their relative use frequency by way of seeing the displayed numbers of hits.
However, the relative estimation of the two search engines lost its validity due to the fact that Yahoo!JAPAN employed Google's search engine in November 2010. Yahoo!JAPAN now returns virtually the same search results as Google does, which implies that Yahoo!JAPAN lost the superiority it used to have over Google.
https://ror.org/035t8zc32 
