According to Ben Edelman, a fellow at The Berkman Center for Internet & Society, it seems that Google's SafeSearch feature is a little too agressive when filtering out possibly offensive material.
He continues: "SafeSearch is intended by Google to block 'pornography and explicit sexual content,' but my research indicates that it blocks far more. SafeSearch is easily confused by ambiguous words in web page titles -- like 'Hardcore Visual Basic Programming,' a web page that describes intense programming for experts, without any sexually-explicit content whatsoever.
"SafeSearch also makes mistakes that are harder to understand -- like filtering the National Middle School Association (nmsa.org) and even the front page of Northeastern University (neu.edu), not to mention numerous sites operated by national and local governments." [Weblogs at Harvard Law]
Uh, oops? Maybe filters like this need to start using the same kind of technology as spam filtering, but in the other direction.