Are search engines responsible for policing the legality of content that they find?
That appears to be the question in front of a BC court that is examining a dispute between IsoHunt and the Canadian Recording Industry Association [petition 
pdf 534K].
While the press accounts are asking if the BC court action could threaten the legality of Google and Yahoo! searches, the real question may be whether search engines will need to respond to requests for take-downs, similar to how YouTube deals with notices of infringement.
It is a case worth watching.