I think we're talking about different things : ) When I consider a search engine obscuring the IP addresses for its search records, I assume the "enemy" is the

I think we're talking about different things : ) When I consider a search engine obscuring the IP addresses for its search records, I assume the "enemy" is the government. It's governments who want to know who's been searching for child porn and bomb-making instructions. They want the IPs, and they can get the algorithm. Now if you're talking about someone with less resources, who can get the obfuscated records but not everything else, your arguments make perfect sense, but I can't imagine who'd be interested other than governments.