Coincidentally, speaking of data centers, an issue that came up today (for me) has been a difference in locale using Yahoo getting different results. But I guess that's a whole other topic, unless there's a difference in browsers with Yahoo as well.... if that's even the case to begin with. One thing for sure is, people are getting different results from the same search engine (ie Google.com, Yahoo.com) for whatever reason, and that seems concerning for relevancy, imho.