Shared Browser History?

With all the talk of shared bookmarks, I’m surprised no one has thought of shared histories. The history file in your browser is a gold mine of preference data, immune to the vagaries of “tagging” and the laziness of an unsalaried distributed librarian workforce. I’d love to see what all my friends were actually viewing, as opposed to just the subset of what they bookmarked. And with Safari private browsing it wouldn’t even expose all the porn the degenerates are wading through.