I searched for "boy" with Safe Search off and Google gave me a count of 496 million results with the Wikipedia article the top result and related searches: Playboy!

Then I turn Safe Search on to check if Playboy goes away. It does, but strangely number of results decreases to 55 million results and the Wikipedia article no longer shows up in the top 10!

Google behaving weirdly... you agree?

I don't think related searches are quite as refined yet.